diff --git a/vendor/github.com/hashicorp/go-immutable-radix/.gitignore b/vendor/github.com/hashicorp/go-immutable-radix/.gitignore
new file mode 100644
index 0000000..daf913b
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-immutable-radix/.gitignore
@@ -0,0 +1,24 @@
+# Compiled Object files, Static and Dynamic libs (Shared Objects)
+*.o
+*.a
+*.so
+
+# Folders
+_obj
+_test
+
+# Architecture specific extensions/prefixes
+*.[568vq]
+[568vq].out
+
+*.cgo1.go
+*.cgo2.c
+_cgo_defun.c
+_cgo_gotypes.go
+_cgo_export.*
+
+_testmain.go
+
+*.exe
+*.test
+*.prof
diff --git a/vendor/github.com/hashicorp/go-immutable-radix/.travis.yml b/vendor/github.com/hashicorp/go-immutable-radix/.travis.yml
new file mode 100644
index 0000000..1a0bbea
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-immutable-radix/.travis.yml
@@ -0,0 +1,3 @@
+language: go
+go:
+  - tip
diff --git a/vendor/github.com/hashicorp/go-immutable-radix/CHANGELOG.md b/vendor/github.com/hashicorp/go-immutable-radix/CHANGELOG.md
new file mode 100644
index 0000000..dd7c0ef
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-immutable-radix/CHANGELOG.md
@@ -0,0 +1,9 @@
+# 1.1.0 (May 22nd, 2019)
+
+FEATURES
+
+* Add `SeekLowerBound` to allow for range scans. [[GH-24](https://github.com/hashicorp/go-immutable-radix/pull/24)]
+
+# 1.0.0 (August 30th, 2018)
+
+* go mod adopted
diff --git a/vendor/github.com/hashicorp/go-immutable-radix/LICENSE b/vendor/github.com/hashicorp/go-immutable-radix/LICENSE
new file mode 100644
index 0000000..e87a115
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-immutable-radix/LICENSE
@@ -0,0 +1,363 @@
+Mozilla Public License, version 2.0
+
+1. Definitions
+
+1.1. "Contributor"
+
+     means each individual or legal entity that creates, contributes to the
+     creation of, or owns Covered Software.
+
+1.2. "Contributor Version"
+
+     means the combination of the Contributions of others (if any) used by a
+     Contributor and that particular Contributor's Contribution.
+
+1.3. "Contribution"
+
+     means Covered Software of a particular Contributor.
+
+1.4. "Covered Software"
+
+     means Source Code Form to which the initial Contributor has attached the
+     notice in Exhibit A, the Executable Form of such Source Code Form, and
+     Modifications of such Source Code Form, in each case including portions
+     thereof.
+
+1.5. "Incompatible With Secondary Licenses"
+     means
+
+     a. that the initial Contributor has attached the notice described in
+        Exhibit B to the Covered Software; or
+
+     b. that the Covered Software was made available under the terms of
+        version 1.1 or earlier of the License, but not also under the terms of
+        a Secondary License.
+
+1.6. "Executable Form"
+
+     means any form of the work other than Source Code Form.
+
+1.7. "Larger Work"
+
+     means a work that combines Covered Software with other material, in a
+     separate file or files, that is not Covered Software.
+
+1.8. "License"
+
+     means this document.
+
+1.9. "Licensable"
+
+     means having the right to grant, to the maximum extent possible, whether
+     at the time of the initial grant or subsequently, any and all of the
+     rights conveyed by this License.
+
+1.10. "Modifications"
+
+     means any of the following:
+
+     a. any file in Source Code Form that results from an addition to,
+        deletion from, or modification of the contents of Covered Software; or
+
+     b. any new file in Source Code Form that contains any Covered Software.
+
+1.11. "Patent Claims" of a Contributor
+
+      means any patent claim(s), including without limitation, method,
+      process, and apparatus claims, in any patent Licensable by such
+      Contributor that would be infringed, but for the grant of the License,
+      by the making, using, selling, offering for sale, having made, import,
+      or transfer of either its Contributions or its Contributor Version.
+
+1.12. "Secondary License"
+
+      means either the GNU General Public License, Version 2.0, the GNU Lesser
+      General Public License, Version 2.1, the GNU Affero General Public
+      License, Version 3.0, or any later versions of those licenses.
+
+1.13. "Source Code Form"
+
+      means the form of the work preferred for making modifications.
+
+1.14. "You" (or "Your")
+
+      means an individual or a legal entity exercising rights under this
+      License. For legal entities, "You" includes any entity that controls, is
+      controlled by, or is under common control with You. For purposes of this
+      definition, "control" means (a) the power, direct or indirect, to cause
+      the direction or management of such entity, whether by contract or
+      otherwise, or (b) ownership of more than fifty percent (50%) of the
+      outstanding shares or beneficial ownership of such entity.
+
+
+2. License Grants and Conditions
+
+2.1. Grants
+
+     Each Contributor hereby grants You a world-wide, royalty-free,
+     non-exclusive license:
+
+     a. under intellectual property rights (other than patent or trademark)
+        Licensable by such Contributor to use, reproduce, make available,
+        modify, display, perform, distribute, and otherwise exploit its
+        Contributions, either on an unmodified basis, with Modifications, or
+        as part of a Larger Work; and
+
+     b. under Patent Claims of such Contributor to make, use, sell, offer for
+        sale, have made, import, and otherwise transfer either its
+        Contributions or its Contributor Version.
+
+2.2. Effective Date
+
+     The licenses granted in Section 2.1 with respect to any Contribution
+     become effective for each Contribution on the date the Contributor first
+     distributes such Contribution.
+
+2.3. Limitations on Grant Scope
+
+     The licenses granted in this Section 2 are the only rights granted under
+     this License. No additional rights or licenses will be implied from the
+     distribution or licensing of Covered Software under this License.
+     Notwithstanding Section 2.1(b) above, no patent license is granted by a
+     Contributor:
+
+     a. for any code that a Contributor has removed from Covered Software; or
+
+     b. for infringements caused by: (i) Your and any other third party's
+        modifications of Covered Software, or (ii) the combination of its
+        Contributions with other software (except as part of its Contributor
+        Version); or
+
+     c. under Patent Claims infringed by Covered Software in the absence of
+        its Contributions.
+
+     This License does not grant any rights in the trademarks, service marks,
+     or logos of any Contributor (except as may be necessary to comply with
+     the notice requirements in Section 3.4).
+
+2.4. Subsequent Licenses
+
+     No Contributor makes additional grants as a result of Your choice to
+     distribute the Covered Software under a subsequent version of this
+     License (see Section 10.2) or under the terms of a Secondary License (if
+     permitted under the terms of Section 3.3).
+
+2.5. Representation
+
+     Each Contributor represents that the Contributor believes its
+     Contributions are its original creation(s) or it has sufficient rights to
+     grant the rights to its Contributions conveyed by this License.
+
+2.6. Fair Use
+
+     This License is not intended to limit any rights You have under
+     applicable copyright doctrines of fair use, fair dealing, or other
+     equivalents.
+
+2.7. Conditions
+
+     Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted in
+     Section 2.1.
+
+
+3. Responsibilities
+
+3.1. Distribution of Source Form
+
+     All distribution of Covered Software in Source Code Form, including any
+     Modifications that You create or to which You contribute, must be under
+     the terms of this License. You must inform recipients that the Source
+     Code Form of the Covered Software is governed by the terms of this
+     License, and how they can obtain a copy of this License. You may not
+     attempt to alter or restrict the recipients' rights in the Source Code
+     Form.
+
+3.2. Distribution of Executable Form
+
+     If You distribute Covered Software in Executable Form then:
+
+     a. such Covered Software must also be made available in Source Code Form,
+        as described in Section 3.1, and You must inform recipients of the
+        Executable Form how they can obtain a copy of such Source Code Form by
+        reasonable means in a timely manner, at a charge no more than the cost
+        of distribution to the recipient; and
+
+     b. You may distribute such Executable Form under the terms of this
+        License, or sublicense it under different terms, provided that the
+        license for the Executable Form does not attempt to limit or alter the
+        recipients' rights in the Source Code Form under this License.
+
+3.3. Distribution of a Larger Work
+
+     You may create and distribute a Larger Work under terms of Your choice,
+     provided that You also comply with the requirements of this License for
+     the Covered Software. If the Larger Work is a combination of Covered
+     Software with a work governed by one or more Secondary Licenses, and the
+     Covered Software is not Incompatible With Secondary Licenses, this
+     License permits You to additionally distribute such Covered Software
+     under the terms of such Secondary License(s), so that the recipient of
+     the Larger Work may, at their option, further distribute the Covered
+     Software under the terms of either this License or such Secondary
+     License(s).
+
+3.4. Notices
+
+     You may not remove or alter the substance of any license notices
+     (including copyright notices, patent notices, disclaimers of warranty, or
+     limitations of liability) contained within the Source Code Form of the
+     Covered Software, except that You may alter any license notices to the
+     extent required to remedy known factual inaccuracies.
+
+3.5. Application of Additional Terms
+
+     You may choose to offer, and to charge a fee for, warranty, support,
+     indemnity or liability obligations to one or more recipients of Covered
+     Software. However, You may do so only on Your own behalf, and not on
+     behalf of any Contributor. You must make it absolutely clear that any
+     such warranty, support, indemnity, or liability obligation is offered by
+     You alone, and You hereby agree to indemnify every Contributor for any
+     liability incurred by such Contributor as a result of warranty, support,
+     indemnity or liability terms You offer. You may include additional
+     disclaimers of warranty and limitations of liability specific to any
+     jurisdiction.
+
+4. Inability to Comply Due to Statute or Regulation
+
+   If it is impossible for You to comply with any of the terms of this License
+   with respect to some or all of the Covered Software due to statute,
+   judicial order, or regulation then You must: (a) comply with the terms of
+   this License to the maximum extent possible; and (b) describe the
+   limitations and the code they affect. Such description must be placed in a
+   text file included with all distributions of the Covered Software under
+   this License. Except to the extent prohibited by statute or regulation,
+   such description must be sufficiently detailed for a recipient of ordinary
+   skill to be able to understand it.
+
+5. Termination
+
+5.1. The rights granted under this License will terminate automatically if You
+     fail to comply with any of its terms. However, if You become compliant,
+     then the rights granted under this License from a particular Contributor
+     are reinstated (a) provisionally, unless and until such Contributor
+     explicitly and finally terminates Your grants, and (b) on an ongoing
+     basis, if such Contributor fails to notify You of the non-compliance by
+     some reasonable means prior to 60 days after You have come back into
+     compliance. Moreover, Your grants from a particular Contributor are
+     reinstated on an ongoing basis if such Contributor notifies You of the
+     non-compliance by some reasonable means, this is the first time You have
+     received notice of non-compliance with this License from such
+     Contributor, and You become compliant prior to 30 days after Your receipt
+     of the notice.
+
+5.2. If You initiate litigation against any entity by asserting a patent
+     infringement claim (excluding declaratory judgment actions,
+     counter-claims, and cross-claims) alleging that a Contributor Version
+     directly or indirectly infringes any patent, then the rights granted to
+     You by any and all Contributors for the Covered Software under Section
+     2.1 of this License shall terminate.
+
+5.3. In the event of termination under Sections 5.1 or 5.2 above, all end user
+     license agreements (excluding distributors and resellers) which have been
+     validly granted by You or Your distributors under this License prior to
+     termination shall survive termination.
+
+6. Disclaimer of Warranty
+
+   Covered Software is provided under this License on an "as is" basis,
+   without warranty of any kind, either expressed, implied, or statutory,
+   including, without limitation, warranties that the Covered Software is free
+   of defects, merchantable, fit for a particular purpose or non-infringing.
+   The entire risk as to the quality and performance of the Covered Software
+   is with You. Should any Covered Software prove defective in any respect,
+   You (not any Contributor) assume the cost of any necessary servicing,
+   repair, or correction. This disclaimer of warranty constitutes an essential
+   part of this License. No use of  any Covered Software is authorized under
+   this License except under this disclaimer.
+
+7. Limitation of Liability
+
+   Under no circumstances and under no legal theory, whether tort (including
+   negligence), contract, or otherwise, shall any Contributor, or anyone who
+   distributes Covered Software as permitted above, be liable to You for any
+   direct, indirect, special, incidental, or consequential damages of any
+   character including, without limitation, damages for lost profits, loss of
+   goodwill, work stoppage, computer failure or malfunction, or any and all
+   other commercial damages or losses, even if such party shall have been
+   informed of the possibility of such damages. This limitation of liability
+   shall not apply to liability for death or personal injury resulting from
+   such party's negligence to the extent applicable law prohibits such
+   limitation. Some jurisdictions do not allow the exclusion or limitation of
+   incidental or consequential damages, so this exclusion and limitation may
+   not apply to You.
+
+8. Litigation
+
+   Any litigation relating to this License may be brought only in the courts
+   of a jurisdiction where the defendant maintains its principal place of
+   business and such litigation shall be governed by laws of that
+   jurisdiction, without reference to its conflict-of-law provisions. Nothing
+   in this Section shall prevent a party's ability to bring cross-claims or
+   counter-claims.
+
+9. Miscellaneous
+
+   This License represents the complete agreement concerning the subject
+   matter hereof. If any provision of this License is held to be
+   unenforceable, such provision shall be reformed only to the extent
+   necessary to make it enforceable. Any law or regulation which provides that
+   the language of a contract shall be construed against the drafter shall not
+   be used to construe this License against a Contributor.
+
+
+10. Versions of the License
+
+10.1. New Versions
+
+      Mozilla Foundation is the license steward. Except as provided in Section
+      10.3, no one other than the license steward has the right to modify or
+      publish new versions of this License. Each version will be given a
+      distinguishing version number.
+
+10.2. Effect of New Versions
+
+      You may distribute the Covered Software under the terms of the version
+      of the License under which You originally received the Covered Software,
+      or under the terms of any subsequent version published by the license
+      steward.
+
+10.3. Modified Versions
+
+      If you create software not governed by this License, and you want to
+      create a new license for such software, you may create and use a
+      modified version of this License if you rename the license and remove
+      any references to the name of the license steward (except to note that
+      such modified license differs from this License).
+
+10.4. Distributing Source Code Form that is Incompatible With Secondary
+      Licenses If You choose to distribute Source Code Form that is
+      Incompatible With Secondary Licenses under the terms of this version of
+      the License, the notice described in Exhibit B of this License must be
+      attached.
+
+Exhibit A - Source Code Form License Notice
+
+      This Source Code Form is subject to the
+      terms of the Mozilla Public License, v.
+      2.0. If a copy of the MPL was not
+      distributed with this file, You can
+      obtain one at
+      http://mozilla.org/MPL/2.0/.
+
+If it is not possible or desirable to put the notice in a particular file,
+then You may include the notice in a location (such as a LICENSE file in a
+relevant directory) where a recipient would be likely to look for such a
+notice.
+
+You may add additional accurate notices of copyright ownership.
+
+Exhibit B - "Incompatible With Secondary Licenses" Notice
+
+      This Source Code Form is "Incompatible
+      With Secondary Licenses", as defined by
+      the Mozilla Public License, v. 2.0.
+
diff --git a/vendor/github.com/hashicorp/go-immutable-radix/README.md b/vendor/github.com/hashicorp/go-immutable-radix/README.md
new file mode 100644
index 0000000..4b6338b
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-immutable-radix/README.md
@@ -0,0 +1,66 @@
+go-immutable-radix [![Build Status](https://travis-ci.org/hashicorp/go-immutable-radix.png)](https://travis-ci.org/hashicorp/go-immutable-radix)
+=========
+
+Provides the `iradix` package that implements an immutable [radix tree](http://en.wikipedia.org/wiki/Radix_tree).
+The package only provides a single `Tree` implementation, optimized for sparse nodes.
+
+As a radix tree, it provides the following:
+ * O(k) operations. In many cases, this can be faster than a hash table since
+   the hash function is an O(k) operation, and hash tables have very poor cache locality.
+ * Minimum / Maximum value lookups
+ * Ordered iteration
+
+A tree supports using a transaction to batch multiple updates (insert, delete)
+in a more efficient manner than performing each operation one at a time.
+
+For a mutable variant, see [go-radix](https://github.com/armon/go-radix).
+
+Documentation
+=============
+
+The full documentation is available on [Godoc](http://godoc.org/github.com/hashicorp/go-immutable-radix).
+
+Example
+=======
+
+Below is a simple example of usage
+
+```go
+// Create a tree
+r := iradix.New()
+r, _, _ = r.Insert([]byte("foo"), 1)
+r, _, _ = r.Insert([]byte("bar"), 2)
+r, _, _ = r.Insert([]byte("foobar"), 2)
+
+// Find the longest prefix match
+m, _, _ := r.Root().LongestPrefix([]byte("foozip"))
+if string(m) != "foo" {
+    panic("should be foo")
+}
+```
+
+Here is an example of performing a range scan of the keys.
+
+```go
+// Create a tree
+r := iradix.New()
+r, _, _ = r.Insert([]byte("001"), 1)
+r, _, _ = r.Insert([]byte("002"), 2)
+r, _, _ = r.Insert([]byte("005"), 5)
+r, _, _ = r.Insert([]byte("010"), 10)
+r, _, _ = r.Insert([]byte("100"), 10)
+
+// Range scan over the keys that sort lexicographically between [003, 050)
+it := r.Root().Iterator()
+it.SeekLowerBound([]byte("003"))
+for key, _, ok := it.Next(); ok; key, _, ok = it.Next() {
+  if key >= "050" {
+      break
+  }
+  fmt.Println(key)
+}
+// Output:
+//  005
+//  010
+```
+
diff --git a/vendor/github.com/hashicorp/go-immutable-radix/edges.go b/vendor/github.com/hashicorp/go-immutable-radix/edges.go
new file mode 100644
index 0000000..a636747
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-immutable-radix/edges.go
@@ -0,0 +1,21 @@
+package iradix
+
+import "sort"
+
+type edges []edge
+
+func (e edges) Len() int {
+	return len(e)
+}
+
+func (e edges) Less(i, j int) bool {
+	return e[i].label < e[j].label
+}
+
+func (e edges) Swap(i, j int) {
+	e[i], e[j] = e[j], e[i]
+}
+
+func (e edges) Sort() {
+	sort.Sort(e)
+}
diff --git a/vendor/github.com/hashicorp/go-immutable-radix/go.mod b/vendor/github.com/hashicorp/go-immutable-radix/go.mod
new file mode 100644
index 0000000..27e7b7c
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-immutable-radix/go.mod
@@ -0,0 +1,6 @@
+module github.com/hashicorp/go-immutable-radix
+
+require (
+	github.com/hashicorp/go-uuid v1.0.0
+	github.com/hashicorp/golang-lru v0.5.0
+)
diff --git a/vendor/github.com/hashicorp/go-immutable-radix/go.sum b/vendor/github.com/hashicorp/go-immutable-radix/go.sum
new file mode 100644
index 0000000..7de5dfc
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-immutable-radix/go.sum
@@ -0,0 +1,4 @@
+github.com/hashicorp/go-uuid v1.0.0 h1:RS8zrF7PhGwyNPOtxSClXXj9HA8feRnJzgnI1RJCSnM=
+github.com/hashicorp/go-uuid v1.0.0/go.mod h1:6SBZvOh/SIDV7/2o3Jml5SYk/TvGqwFJ/bN7x4byOro=
+github.com/hashicorp/golang-lru v0.5.0 h1:CL2msUPvZTLb5O648aiLNJw3hnBxN2+1Jq8rCOH9wdo=
+github.com/hashicorp/golang-lru v0.5.0/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ4Ao+sR/qLZy8=
diff --git a/vendor/github.com/hashicorp/go-immutable-radix/iradix.go b/vendor/github.com/hashicorp/go-immutable-radix/iradix.go
new file mode 100644
index 0000000..e5e6e57
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-immutable-radix/iradix.go
@@ -0,0 +1,662 @@
+package iradix
+
+import (
+	"bytes"
+	"strings"
+
+	"github.com/hashicorp/golang-lru/simplelru"
+)
+
+const (
+	// defaultModifiedCache is the default size of the modified node
+	// cache used per transaction. This is used to cache the updates
+	// to the nodes near the root, while the leaves do not need to be
+	// cached. This is important for very large transactions to prevent
+	// the modified cache from growing to be enormous. This is also used
+	// to set the max size of the mutation notify maps since those should
+	// also be bounded in a similar way.
+	defaultModifiedCache = 8192
+)
+
+// Tree implements an immutable radix tree. This can be treated as a
+// Dictionary abstract data type. The main advantage over a standard
+// hash map is prefix-based lookups and ordered iteration. The immutability
+// means that it is safe to concurrently read from a Tree without any
+// coordination.
+type Tree struct {
+	root *Node
+	size int
+}
+
+// New returns an empty Tree
+func New() *Tree {
+	t := &Tree{
+		root: &Node{
+			mutateCh: make(chan struct{}),
+		},
+	}
+	return t
+}
+
+// Len is used to return the number of elements in the tree
+func (t *Tree) Len() int {
+	return t.size
+}
+
+// Txn is a transaction on the tree. This transaction is applied
+// atomically and returns a new tree when committed. A transaction
+// is not thread safe, and should only be used by a single goroutine.
+type Txn struct {
+	// root is the modified root for the transaction.
+	root *Node
+
+	// snap is a snapshot of the root node for use if we have to run the
+	// slow notify algorithm.
+	snap *Node
+
+	// size tracks the size of the tree as it is modified during the
+	// transaction.
+	size int
+
+	// writable is a cache of writable nodes that have been created during
+	// the course of the transaction. This allows us to re-use the same
+	// nodes for further writes and avoid unnecessary copies of nodes that
+	// have never been exposed outside the transaction. This will only hold
+	// up to defaultModifiedCache number of entries.
+	writable *simplelru.LRU
+
+	// trackChannels is used to hold channels that need to be notified to
+	// signal mutation of the tree. This will only hold up to
+	// defaultModifiedCache number of entries, after which we will set the
+	// trackOverflow flag, which will cause us to use a more expensive
+	// algorithm to perform the notifications. Mutation tracking is only
+	// performed if trackMutate is true.
+	trackChannels map[chan struct{}]struct{}
+	trackOverflow bool
+	trackMutate   bool
+}
+
+// Txn starts a new transaction that can be used to mutate the tree
+func (t *Tree) Txn() *Txn {
+	txn := &Txn{
+		root: t.root,
+		snap: t.root,
+		size: t.size,
+	}
+	return txn
+}
+
+// TrackMutate can be used to toggle if mutations are tracked. If this is enabled
+// then notifications will be issued for affected internal nodes and leaves when
+// the transaction is committed.
+func (t *Txn) TrackMutate(track bool) {
+	t.trackMutate = track
+}
+
+// trackChannel safely attempts to track the given mutation channel, setting the
+// overflow flag if we can no longer track any more. This limits the amount of
+// state that will accumulate during a transaction and we have a slower algorithm
+// to switch to if we overflow.
+func (t *Txn) trackChannel(ch chan struct{}) {
+	// In overflow, make sure we don't store any more objects.
+	if t.trackOverflow {
+		return
+	}
+
+	// If this would overflow the state we reject it and set the flag (since
+	// we aren't tracking everything that's required any longer).
+	if len(t.trackChannels) >= defaultModifiedCache {
+		// Mark that we are in the overflow state
+		t.trackOverflow = true
+
+		// Clear the map so that the channels can be garbage collected. It is
+		// safe to do this since we have already overflowed and will be using
+		// the slow notify algorithm.
+		t.trackChannels = nil
+		return
+	}
+
+	// Create the map on the fly when we need it.
+	if t.trackChannels == nil {
+		t.trackChannels = make(map[chan struct{}]struct{})
+	}
+
+	// Otherwise we are good to track it.
+	t.trackChannels[ch] = struct{}{}
+}
+
+// writeNode returns a node to be modified, if the current node has already been
+// modified during the course of the transaction, it is used in-place. Set
+// forLeafUpdate to true if you are getting a write node to update the leaf,
+// which will set leaf mutation tracking appropriately as well.
+func (t *Txn) writeNode(n *Node, forLeafUpdate bool) *Node {
+	// Ensure the writable set exists.
+	if t.writable == nil {
+		lru, err := simplelru.NewLRU(defaultModifiedCache, nil)
+		if err != nil {
+			panic(err)
+		}
+		t.writable = lru
+	}
+
+	// If this node has already been modified, we can continue to use it
+	// during this transaction. We know that we don't need to track it for
+	// a node update since the node is writable, but if this is for a leaf
+	// update we track it, in case the initial write to this node didn't
+	// update the leaf.
+	if _, ok := t.writable.Get(n); ok {
+		if t.trackMutate && forLeafUpdate && n.leaf != nil {
+			t.trackChannel(n.leaf.mutateCh)
+		}
+		return n
+	}
+
+	// Mark this node as being mutated.
+	if t.trackMutate {
+		t.trackChannel(n.mutateCh)
+	}
+
+	// Mark its leaf as being mutated, if appropriate.
+	if t.trackMutate && forLeafUpdate && n.leaf != nil {
+		t.trackChannel(n.leaf.mutateCh)
+	}
+
+	// Copy the existing node. If you have set forLeafUpdate it will be
+	// safe to replace this leaf with another after you get your node for
+	// writing. You MUST replace it, because the channel associated with
+	// this leaf will be closed when this transaction is committed.
+	nc := &Node{
+		mutateCh: make(chan struct{}),
+		leaf:     n.leaf,
+	}
+	if n.prefix != nil {
+		nc.prefix = make([]byte, len(n.prefix))
+		copy(nc.prefix, n.prefix)
+	}
+	if len(n.edges) != 0 {
+		nc.edges = make([]edge, len(n.edges))
+		copy(nc.edges, n.edges)
+	}
+
+	// Mark this node as writable.
+	t.writable.Add(nc, nil)
+	return nc
+}
+
+// Visit all the nodes in the tree under n, and add their mutateChannels to the transaction
+// Returns the size of the subtree visited
+func (t *Txn) trackChannelsAndCount(n *Node) int {
+	// Count only leaf nodes
+	leaves := 0
+	if n.leaf != nil {
+		leaves = 1
+	}
+	// Mark this node as being mutated.
+	if t.trackMutate {
+		t.trackChannel(n.mutateCh)
+	}
+
+	// Mark its leaf as being mutated, if appropriate.
+	if t.trackMutate && n.leaf != nil {
+		t.trackChannel(n.leaf.mutateCh)
+	}
+
+	// Recurse on the children
+	for _, e := range n.edges {
+		leaves += t.trackChannelsAndCount(e.node)
+	}
+	return leaves
+}
+
+// mergeChild is called to collapse the given node with its child. This is only
+// called when the given node is not a leaf and has a single edge.
+func (t *Txn) mergeChild(n *Node) {
+	// Mark the child node as being mutated since we are about to abandon
+	// it. We don't need to mark the leaf since we are retaining it if it
+	// is there.
+	e := n.edges[0]
+	child := e.node
+	if t.trackMutate {
+		t.trackChannel(child.mutateCh)
+	}
+
+	// Merge the nodes.
+	n.prefix = concat(n.prefix, child.prefix)
+	n.leaf = child.leaf
+	if len(child.edges) != 0 {
+		n.edges = make([]edge, len(child.edges))
+		copy(n.edges, child.edges)
+	} else {
+		n.edges = nil
+	}
+}
+
+// insert does a recursive insertion
+func (t *Txn) insert(n *Node, k, search []byte, v interface{}) (*Node, interface{}, bool) {
+	// Handle key exhaustion
+	if len(search) == 0 {
+		var oldVal interface{}
+		didUpdate := false
+		if n.isLeaf() {
+			oldVal = n.leaf.val
+			didUpdate = true
+		}
+
+		nc := t.writeNode(n, true)
+		nc.leaf = &leafNode{
+			mutateCh: make(chan struct{}),
+			key:      k,
+			val:      v,
+		}
+		return nc, oldVal, didUpdate
+	}
+
+	// Look for the edge
+	idx, child := n.getEdge(search[0])
+
+	// No edge, create one
+	if child == nil {
+		e := edge{
+			label: search[0],
+			node: &Node{
+				mutateCh: make(chan struct{}),
+				leaf: &leafNode{
+					mutateCh: make(chan struct{}),
+					key:      k,
+					val:      v,
+				},
+				prefix: search,
+			},
+		}
+		nc := t.writeNode(n, false)
+		nc.addEdge(e)
+		return nc, nil, false
+	}
+
+	// Determine longest prefix of the search key on match
+	commonPrefix := longestPrefix(search, child.prefix)
+	if commonPrefix == len(child.prefix) {
+		search = search[commonPrefix:]
+		newChild, oldVal, didUpdate := t.insert(child, k, search, v)
+		if newChild != nil {
+			nc := t.writeNode(n, false)
+			nc.edges[idx].node = newChild
+			return nc, oldVal, didUpdate
+		}
+		return nil, oldVal, didUpdate
+	}
+
+	// Split the node
+	nc := t.writeNode(n, false)
+	splitNode := &Node{
+		mutateCh: make(chan struct{}),
+		prefix:   search[:commonPrefix],
+	}
+	nc.replaceEdge(edge{
+		label: search[0],
+		node:  splitNode,
+	})
+
+	// Restore the existing child node
+	modChild := t.writeNode(child, false)
+	splitNode.addEdge(edge{
+		label: modChild.prefix[commonPrefix],
+		node:  modChild,
+	})
+	modChild.prefix = modChild.prefix[commonPrefix:]
+
+	// Create a new leaf node
+	leaf := &leafNode{
+		mutateCh: make(chan struct{}),
+		key:      k,
+		val:      v,
+	}
+
+	// If the new key is a subset, add to to this node
+	search = search[commonPrefix:]
+	if len(search) == 0 {
+		splitNode.leaf = leaf
+		return nc, nil, false
+	}
+
+	// Create a new edge for the node
+	splitNode.addEdge(edge{
+		label: search[0],
+		node: &Node{
+			mutateCh: make(chan struct{}),
+			leaf:     leaf,
+			prefix:   search,
+		},
+	})
+	return nc, nil, false
+}
+
+// delete does a recursive deletion
+func (t *Txn) delete(parent, n *Node, search []byte) (*Node, *leafNode) {
+	// Check for key exhaustion
+	if len(search) == 0 {
+		if !n.isLeaf() {
+			return nil, nil
+		}
+		// Copy the pointer in case we are in a transaction that already
+		// modified this node since the node will be reused. Any changes
+		// made to the node will not affect returning the original leaf
+		// value.
+		oldLeaf := n.leaf
+
+		// Remove the leaf node
+		nc := t.writeNode(n, true)
+		nc.leaf = nil
+
+		// Check if this node should be merged
+		if n != t.root && len(nc.edges) == 1 {
+			t.mergeChild(nc)
+		}
+		return nc, oldLeaf
+	}
+
+	// Look for an edge
+	label := search[0]
+	idx, child := n.getEdge(label)
+	if child == nil || !bytes.HasPrefix(search, child.prefix) {
+		return nil, nil
+	}
+
+	// Consume the search prefix
+	search = search[len(child.prefix):]
+	newChild, leaf := t.delete(n, child, search)
+	if newChild == nil {
+		return nil, nil
+	}
+
+	// Copy this node. WATCH OUT - it's safe to pass "false" here because we
+	// will only ADD a leaf via nc.mergeChild() if there isn't one due to
+	// the !nc.isLeaf() check in the logic just below. This is pretty subtle,
+	// so be careful if you change any of the logic here.
+	nc := t.writeNode(n, false)
+
+	// Delete the edge if the node has no edges
+	if newChild.leaf == nil && len(newChild.edges) == 0 {
+		nc.delEdge(label)
+		if n != t.root && len(nc.edges) == 1 && !nc.isLeaf() {
+			t.mergeChild(nc)
+		}
+	} else {
+		nc.edges[idx].node = newChild
+	}
+	return nc, leaf
+}
+
+// delete does a recursive deletion
+func (t *Txn) deletePrefix(parent, n *Node, search []byte) (*Node, int) {
+	// Check for key exhaustion
+	if len(search) == 0 {
+		nc := t.writeNode(n, true)
+		if n.isLeaf() {
+			nc.leaf = nil
+		}
+		nc.edges = nil
+		return nc, t.trackChannelsAndCount(n)
+	}
+
+	// Look for an edge
+	label := search[0]
+	idx, child := n.getEdge(label)
+	// We make sure that either the child node's prefix starts with the search term, or the search term starts with the child node's prefix
+	// Need to do both so that we can delete prefixes that don't correspond to any node in the tree
+	if child == nil || (!bytes.HasPrefix(child.prefix, search) && !bytes.HasPrefix(search, child.prefix)) {
+		return nil, 0
+	}
+
+	// Consume the search prefix
+	if len(child.prefix) > len(search) {
+		search = []byte("")
+	} else {
+		search = search[len(child.prefix):]
+	}
+	newChild, numDeletions := t.deletePrefix(n, child, search)
+	if newChild == nil {
+		return nil, 0
+	}
+	// Copy this node. WATCH OUT - it's safe to pass "false" here because we
+	// will only ADD a leaf via nc.mergeChild() if there isn't one due to
+	// the !nc.isLeaf() check in the logic just below. This is pretty subtle,
+	// so be careful if you change any of the logic here.
+
+	nc := t.writeNode(n, false)
+
+	// Delete the edge if the node has no edges
+	if newChild.leaf == nil && len(newChild.edges) == 0 {
+		nc.delEdge(label)
+		if n != t.root && len(nc.edges) == 1 && !nc.isLeaf() {
+			t.mergeChild(nc)
+		}
+	} else {
+		nc.edges[idx].node = newChild
+	}
+	return nc, numDeletions
+}
+
+// Insert is used to add or update a given key. The return provides
+// the previous value and a bool indicating if any was set.
+func (t *Txn) Insert(k []byte, v interface{}) (interface{}, bool) {
+	newRoot, oldVal, didUpdate := t.insert(t.root, k, k, v)
+	if newRoot != nil {
+		t.root = newRoot
+	}
+	if !didUpdate {
+		t.size++
+	}
+	return oldVal, didUpdate
+}
+
+// Delete is used to delete a given key. Returns the old value if any,
+// and a bool indicating if the key was set.
+func (t *Txn) Delete(k []byte) (interface{}, bool) {
+	newRoot, leaf := t.delete(nil, t.root, k)
+	if newRoot != nil {
+		t.root = newRoot
+	}
+	if leaf != nil {
+		t.size--
+		return leaf.val, true
+	}
+	return nil, false
+}
+
+// DeletePrefix is used to delete an entire subtree that matches the prefix
+// This will delete all nodes under that prefix
+func (t *Txn) DeletePrefix(prefix []byte) bool {
+	newRoot, numDeletions := t.deletePrefix(nil, t.root, prefix)
+	if newRoot != nil {
+		t.root = newRoot
+		t.size = t.size - numDeletions
+		return true
+	}
+	return false
+
+}
+
+// Root returns the current root of the radix tree within this
+// transaction. The root is not safe across insert and delete operations,
+// but can be used to read the current state during a transaction.
+func (t *Txn) Root() *Node {
+	return t.root
+}
+
+// Get is used to lookup a specific key, returning
+// the value and if it was found
+func (t *Txn) Get(k []byte) (interface{}, bool) {
+	return t.root.Get(k)
+}
+
+// GetWatch is used to lookup a specific key, returning
+// the watch channel, value and if it was found
+func (t *Txn) GetWatch(k []byte) (<-chan struct{}, interface{}, bool) {
+	return t.root.GetWatch(k)
+}
+
+// Commit is used to finalize the transaction and return a new tree. If mutation
+// tracking is turned on then notifications will also be issued.
+func (t *Txn) Commit() *Tree {
+	nt := t.CommitOnly()
+	if t.trackMutate {
+		t.Notify()
+	}
+	return nt
+}
+
+// CommitOnly is used to finalize the transaction and return a new tree, but
+// does not issue any notifications until Notify is called.
+func (t *Txn) CommitOnly() *Tree {
+	nt := &Tree{t.root, t.size}
+	t.writable = nil
+	return nt
+}
+
+// slowNotify does a complete comparison of the before and after trees in order
+// to trigger notifications. This doesn't require any additional state but it
+// is very expensive to compute.
+func (t *Txn) slowNotify() {
+	snapIter := t.snap.rawIterator()
+	rootIter := t.root.rawIterator()
+	for snapIter.Front() != nil || rootIter.Front() != nil {
+		// If we've exhausted the nodes in the old snapshot, we know
+		// there's nothing remaining to notify.
+		if snapIter.Front() == nil {
+			return
+		}
+		snapElem := snapIter.Front()
+
+		// If we've exhausted the nodes in the new root, we know we need
+		// to invalidate everything that remains in the old snapshot. We
+		// know from the loop condition there's something in the old
+		// snapshot.
+		if rootIter.Front() == nil {
+			close(snapElem.mutateCh)
+			if snapElem.isLeaf() {
+				close(snapElem.leaf.mutateCh)
+			}
+			snapIter.Next()
+			continue
+		}
+
+		// Do one string compare so we can check the various conditions
+		// below without repeating the compare.
+		cmp := strings.Compare(snapIter.Path(), rootIter.Path())
+
+		// If the snapshot is behind the root, then we must have deleted
+		// this node during the transaction.
+		if cmp < 0 {
+			close(snapElem.mutateCh)
+			if snapElem.isLeaf() {
+				close(snapElem.leaf.mutateCh)
+			}
+			snapIter.Next()
+			continue
+		}
+
+		// If the snapshot is ahead of the root, then we must have added
+		// this node during the transaction.
+		if cmp > 0 {
+			rootIter.Next()
+			continue
+		}
+
+		// If we have the same path, then we need to see if we mutated a
+		// node and possibly the leaf.
+		rootElem := rootIter.Front()
+		if snapElem != rootElem {
+			close(snapElem.mutateCh)
+			if snapElem.leaf != nil && (snapElem.leaf != rootElem.leaf) {
+				close(snapElem.leaf.mutateCh)
+			}
+		}
+		snapIter.Next()
+		rootIter.Next()
+	}
+}
+
+// Notify is used along with TrackMutate to trigger notifications. This must
+// only be done once a transaction is committed via CommitOnly, and it is called
+// automatically by Commit.
+func (t *Txn) Notify() {
+	if !t.trackMutate {
+		return
+	}
+
+	// If we've overflowed the tracking state we can't use it in any way and
+	// need to do a full tree compare.
+	if t.trackOverflow {
+		t.slowNotify()
+	} else {
+		for ch := range t.trackChannels {
+			close(ch)
+		}
+	}
+
+	// Clean up the tracking state so that a re-notify is safe (will trigger
+	// the else clause above which will be a no-op).
+	t.trackChannels = nil
+	t.trackOverflow = false
+}
+
+// Insert is used to add or update a given key. The return provides
+// the new tree, previous value and a bool indicating if any was set.
+func (t *Tree) Insert(k []byte, v interface{}) (*Tree, interface{}, bool) {
+	txn := t.Txn()
+	old, ok := txn.Insert(k, v)
+	return txn.Commit(), old, ok
+}
+
+// Delete is used to delete a given key. Returns the new tree,
+// old value if any, and a bool indicating if the key was set.
+func (t *Tree) Delete(k []byte) (*Tree, interface{}, bool) {
+	txn := t.Txn()
+	old, ok := txn.Delete(k)
+	return txn.Commit(), old, ok
+}
+
+// DeletePrefix is used to delete all nodes starting with a given prefix. Returns the new tree,
+// and a bool indicating if the prefix matched any nodes
+func (t *Tree) DeletePrefix(k []byte) (*Tree, bool) {
+	txn := t.Txn()
+	ok := txn.DeletePrefix(k)
+	return txn.Commit(), ok
+}
+
+// Root returns the root node of the tree which can be used for richer
+// query operations.
+func (t *Tree) Root() *Node {
+	return t.root
+}
+
+// Get is used to lookup a specific key, returning
+// the value and if it was found
+func (t *Tree) Get(k []byte) (interface{}, bool) {
+	return t.root.Get(k)
+}
+
+// longestPrefix finds the length of the shared prefix
+// of two strings
+func longestPrefix(k1, k2 []byte) int {
+	max := len(k1)
+	if l := len(k2); l < max {
+		max = l
+	}
+	var i int
+	for i = 0; i < max; i++ {
+		if k1[i] != k2[i] {
+			break
+		}
+	}
+	return i
+}
+
+// concat two byte slices, returning a third new copy
+func concat(a, b []byte) []byte {
+	c := make([]byte, len(a)+len(b))
+	copy(c, a)
+	copy(c[len(a):], b)
+	return c
+}
diff --git a/vendor/github.com/hashicorp/go-immutable-radix/iter.go b/vendor/github.com/hashicorp/go-immutable-radix/iter.go
new file mode 100644
index 0000000..1ecaf83
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-immutable-radix/iter.go
@@ -0,0 +1,188 @@
+package iradix
+
+import (
+	"bytes"
+)
+
+// Iterator is used to iterate over a set of nodes
+// in pre-order
+type Iterator struct {
+	node  *Node
+	stack []edges
+}
+
+// SeekPrefixWatch is used to seek the iterator to a given prefix
+// and returns the watch channel of the finest granularity
+func (i *Iterator) SeekPrefixWatch(prefix []byte) (watch <-chan struct{}) {
+	// Wipe the stack
+	i.stack = nil
+	n := i.node
+	watch = n.mutateCh
+	search := prefix
+	for {
+		// Check for key exhaution
+		if len(search) == 0 {
+			i.node = n
+			return
+		}
+
+		// Look for an edge
+		_, n = n.getEdge(search[0])
+		if n == nil {
+			i.node = nil
+			return
+		}
+
+		// Update to the finest granularity as the search makes progress
+		watch = n.mutateCh
+
+		// Consume the search prefix
+		if bytes.HasPrefix(search, n.prefix) {
+			search = search[len(n.prefix):]
+
+		} else if bytes.HasPrefix(n.prefix, search) {
+			i.node = n
+			return
+		} else {
+			i.node = nil
+			return
+		}
+	}
+}
+
+// SeekPrefix is used to seek the iterator to a given prefix
+func (i *Iterator) SeekPrefix(prefix []byte) {
+	i.SeekPrefixWatch(prefix)
+}
+
+func (i *Iterator) recurseMin(n *Node) *Node {
+	// Traverse to the minimum child
+	if n.leaf != nil {
+		return n
+	}
+	if len(n.edges) > 0 {
+		// Add all the other edges to the stack (the min node will be added as
+		// we recurse)
+		i.stack = append(i.stack, n.edges[1:])
+		return i.recurseMin(n.edges[0].node)
+	}
+	// Shouldn't be possible
+	return nil
+}
+
+// SeekLowerBound is used to seek the iterator to the smallest key that is
+// greater or equal to the given key. There is no watch variant as it's hard to
+// predict based on the radix structure which node(s) changes might affect the
+// result.
+func (i *Iterator) SeekLowerBound(key []byte) {
+	// Wipe the stack. Unlike Prefix iteration, we need to build the stack as we
+	// go because we need only a subset of edges of many nodes in the path to the
+	// leaf with the lower bound.
+	i.stack = []edges{}
+	n := i.node
+	search := key
+
+	found := func(n *Node) {
+		i.node = n
+		i.stack = append(i.stack, edges{edge{node: n}})
+	}
+
+	for {
+		// Compare current prefix with the search key's same-length prefix.
+		var prefixCmp int
+		if len(n.prefix) < len(search) {
+			prefixCmp = bytes.Compare(n.prefix, search[0:len(n.prefix)])
+		} else {
+			prefixCmp = bytes.Compare(n.prefix, search)
+		}
+
+		if prefixCmp > 0 {
+			// Prefix is larger, that means the lower bound is greater than the search
+			// and from now on we need to follow the minimum path to the smallest
+			// leaf under this subtree.
+			n = i.recurseMin(n)
+			if n != nil {
+				found(n)
+			}
+			return
+		}
+
+		if prefixCmp < 0 {
+			// Prefix is smaller than search prefix, that means there is no lower
+			// bound
+			i.node = nil
+			return
+		}
+
+		// Prefix is equal, we are still heading for an exact match. If this is a
+		// leaf we're done.
+		if n.leaf != nil {
+			if bytes.Compare(n.leaf.key, key) < 0 {
+				i.node = nil
+				return
+			}
+			found(n)
+			return
+		}
+
+		// Consume the search prefix
+		if len(n.prefix) > len(search) {
+			search = []byte{}
+		} else {
+			search = search[len(n.prefix):]
+		}
+
+		// Otherwise, take the lower bound next edge.
+		idx, lbNode := n.getLowerBoundEdge(search[0])
+		if lbNode == nil {
+			i.node = nil
+			return
+		}
+
+		// Create stack edges for the all strictly higher edges in this node.
+		if idx+1 < len(n.edges) {
+			i.stack = append(i.stack, n.edges[idx+1:])
+		}
+
+		i.node = lbNode
+		// Recurse
+		n = lbNode
+	}
+}
+
+// Next returns the next node in order
+func (i *Iterator) Next() ([]byte, interface{}, bool) {
+	// Initialize our stack if needed
+	if i.stack == nil && i.node != nil {
+		i.stack = []edges{
+			edges{
+				edge{node: i.node},
+			},
+		}
+	}
+
+	for len(i.stack) > 0 {
+		// Inspect the last element of the stack
+		n := len(i.stack)
+		last := i.stack[n-1]
+		elem := last[0].node
+
+		// Update the stack
+		if len(last) > 1 {
+			i.stack[n-1] = last[1:]
+		} else {
+			i.stack = i.stack[:n-1]
+		}
+
+		// Push the edges onto the frontier
+		if len(elem.edges) > 0 {
+			i.stack = append(i.stack, elem.edges)
+		}
+
+		// Return the leaf values if any
+		if elem.leaf != nil {
+			return elem.leaf.key, elem.leaf.val, true
+		}
+	}
+	return nil, nil, false
+}
diff --git a/vendor/github.com/hashicorp/go-immutable-radix/node.go b/vendor/github.com/hashicorp/go-immutable-radix/node.go
new file mode 100644
index 0000000..3ab904e
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-immutable-radix/node.go
@@ -0,0 +1,304 @@
+package iradix
+
+import (
+	"bytes"
+	"sort"
+)
+
+// WalkFn is used when walking the tree. Takes a
+// key and value, returning if iteration should
+// be terminated.
+type WalkFn func(k []byte, v interface{}) bool
+
+// leafNode is used to represent a value
+type leafNode struct {
+	mutateCh chan struct{}
+	key      []byte
+	val      interface{}
+}
+
+// edge is used to represent an edge node
+type edge struct {
+	label byte
+	node  *Node
+}
+
+// Node is an immutable node in the radix tree
+type Node struct {
+	// mutateCh is closed if this node is modified
+	mutateCh chan struct{}
+
+	// leaf is used to store possible leaf
+	leaf *leafNode
+
+	// prefix is the common prefix we ignore
+	prefix []byte
+
+	// Edges should be stored in-order for iteration.
+	// We avoid a fully materialized slice to save memory,
+	// since in most cases we expect to be sparse
+	edges edges
+}
+
+func (n *Node) isLeaf() bool {
+	return n.leaf != nil
+}
+
+func (n *Node) addEdge(e edge) {
+	num := len(n.edges)
+	idx := sort.Search(num, func(i int) bool {
+		return n.edges[i].label >= e.label
+	})
+	n.edges = append(n.edges, e)
+	if idx != num {
+		copy(n.edges[idx+1:], n.edges[idx:num])
+		n.edges[idx] = e
+	}
+}
+
+func (n *Node) replaceEdge(e edge) {
+	num := len(n.edges)
+	idx := sort.Search(num, func(i int) bool {
+		return n.edges[i].label >= e.label
+	})
+	if idx < num && n.edges[idx].label == e.label {
+		n.edges[idx].node = e.node
+		return
+	}
+	panic("replacing missing edge")
+}
+
+func (n *Node) getEdge(label byte) (int, *Node) {
+	num := len(n.edges)
+	idx := sort.Search(num, func(i int) bool {
+		return n.edges[i].label >= label
+	})
+	if idx < num && n.edges[idx].label == label {
+		return idx, n.edges[idx].node
+	}
+	return -1, nil
+}
+
+func (n *Node) getLowerBoundEdge(label byte) (int, *Node) {
+	num := len(n.edges)
+	idx := sort.Search(num, func(i int) bool {
+		return n.edges[i].label >= label
+	})
+	// we want lower bound behavior so return even if it's not an exact match
+	if idx < num {
+		return idx, n.edges[idx].node
+	}
+	return -1, nil
+}
+
+func (n *Node) delEdge(label byte) {
+	num := len(n.edges)
+	idx := sort.Search(num, func(i int) bool {
+		return n.edges[i].label >= label
+	})
+	if idx < num && n.edges[idx].label == label {
+		copy(n.edges[idx:], n.edges[idx+1:])
+		n.edges[len(n.edges)-1] = edge{}
+		n.edges = n.edges[:len(n.edges)-1]
+	}
+}
+
+func (n *Node) GetWatch(k []byte) (<-chan struct{}, interface{}, bool) {
+	search := k
+	watch := n.mutateCh
+	for {
+		// Check for key exhaustion
+		if len(search) == 0 {
+			if n.isLeaf() {
+				return n.leaf.mutateCh, n.leaf.val, true
+			}
+			break
+		}
+
+		// Look for an edge
+		_, n = n.getEdge(search[0])
+		if n == nil {
+			break
+		}
+
+		// Update to the finest granularity as the search makes progress
+		watch = n.mutateCh
+
+		// Consume the search prefix
+		if bytes.HasPrefix(search, n.prefix) {
+			search = search[len(n.prefix):]
+		} else {
+			break
+		}
+	}
+	return watch, nil, false
+}
+
+func (n *Node) Get(k []byte) (interface{}, bool) {
+	_, val, ok := n.GetWatch(k)
+	return val, ok
+}
+
+// LongestPrefix is like Get, but instead of an
+// exact match, it will return the longest prefix match.
+func (n *Node) LongestPrefix(k []byte) ([]byte, interface{}, bool) {
+	var last *leafNode
+	search := k
+	for {
+		// Look for a leaf node
+		if n.isLeaf() {
+			last = n.leaf
+		}
+
+		// Check for key exhaution
+		if len(search) == 0 {
+			break
+		}
+
+		// Look for an edge
+		_, n = n.getEdge(search[0])
+		if n == nil {
+			break
+		}
+
+		// Consume the search prefix
+		if bytes.HasPrefix(search, n.prefix) {
+			search = search[len(n.prefix):]
+		} else {
+			break
+		}
+	}
+	if last != nil {
+		return last.key, last.val, true
+	}
+	return nil, nil, false
+}
+
+// Minimum is used to return the minimum value in the tree
+func (n *Node) Minimum() ([]byte, interface{}, bool) {
+	for {
+		if n.isLeaf() {
+			return n.leaf.key, n.leaf.val, true
+		}
+		if len(n.edges) > 0 {
+			n = n.edges[0].node
+		} else {
+			break
+		}
+	}
+	return nil, nil, false
+}
+
+// Maximum is used to return the maximum value in the tree
+func (n *Node) Maximum() ([]byte, interface{}, bool) {
+	for {
+		if num := len(n.edges); num > 0 {
+			n = n.edges[num-1].node
+			continue
+		}
+		if n.isLeaf() {
+			return n.leaf.key, n.leaf.val, true
+		} else {
+			break
+		}
+	}
+	return nil, nil, false
+}
+
+// Iterator is used to return an iterator at
+// the given node to walk the tree
+func (n *Node) Iterator() *Iterator {
+	return &Iterator{node: n}
+}
+
+// rawIterator is used to return a raw iterator at the given node to walk the
+// tree.
+func (n *Node) rawIterator() *rawIterator {
+	iter := &rawIterator{node: n}
+	iter.Next()
+	return iter
+}
+
+// Walk is used to walk the tree
+func (n *Node) Walk(fn WalkFn) {
+	recursiveWalk(n, fn)
+}
+
+// WalkPrefix is used to walk the tree under a prefix
+func (n *Node) WalkPrefix(prefix []byte, fn WalkFn) {
+	search := prefix
+	for {
+		// Check for key exhaution
+		if len(search) == 0 {
+			recursiveWalk(n, fn)
+			return
+		}
+
+		// Look for an edge
+		_, n = n.getEdge(search[0])
+		if n == nil {
+			break
+		}
+
+		// Consume the search prefix
+		if bytes.HasPrefix(search, n.prefix) {
+			search = search[len(n.prefix):]
+
+		} else if bytes.HasPrefix(n.prefix, search) {
+			// Child may be under our search prefix
+			recursiveWalk(n, fn)
+			return
+		} else {
+			break
+		}
+	}
+}
+
+// WalkPath is used to walk the tree, but only visiting nodes
+// from the root down to a given leaf. Where WalkPrefix walks
+// all the entries *under* the given prefix, this walks the
+// entries *above* the given prefix.
+func (n *Node) WalkPath(path []byte, fn WalkFn) {
+	search := path
+	for {
+		// Visit the leaf values if any
+		if n.leaf != nil && fn(n.leaf.key, n.leaf.val) {
+			return
+		}
+
+		// Check for key exhaution
+		if len(search) == 0 {
+			return
+		}
+
+		// Look for an edge
+		_, n = n.getEdge(search[0])
+		if n == nil {
+			return
+		}
+
+		// Consume the search prefix
+		if bytes.HasPrefix(search, n.prefix) {
+			search = search[len(n.prefix):]
+		} else {
+			break
+		}
+	}
+}
+
+// recursiveWalk is used to do a pre-order walk of a node
+// recursively. Returns true if the walk should be aborted
+func recursiveWalk(n *Node, fn WalkFn) bool {
+	// Visit the leaf values if any
+	if n.leaf != nil && fn(n.leaf.key, n.leaf.val) {
+		return true
+	}
+
+	// Recurse on the children
+	for _, e := range n.edges {
+		if recursiveWalk(e.node, fn) {
+			return true
+		}
+	}
+	return false
+}
diff --git a/vendor/github.com/hashicorp/go-immutable-radix/raw_iter.go b/vendor/github.com/hashicorp/go-immutable-radix/raw_iter.go
new file mode 100644
index 0000000..04814c1
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-immutable-radix/raw_iter.go
@@ -0,0 +1,78 @@
+package iradix
+
+// rawIterator visits each of the nodes in the tree, even the ones that are not
+// leaves. It keeps track of the effective path (what a leaf at a given node
+// would be called), which is useful for comparing trees.
+type rawIterator struct {
+	// node is the starting node in the tree for the iterator.
+	node *Node
+
+	// stack keeps track of edges in the frontier.
+	stack []rawStackEntry
+
+	// pos is the current position of the iterator.
+	pos *Node
+
+	// path is the effective path of the current iterator position,
+	// regardless of whether the current node is a leaf.
+	path string
+}
+
+// rawStackEntry is used to keep track of the cumulative common path as well as
+// its associated edges in the frontier.
+type rawStackEntry struct {
+	path  string
+	edges edges
+}
+
+// Front returns the current node that has been iterated to.
+func (i *rawIterator) Front() *Node {
+	return i.pos
+}
+
+// Path returns the effective path of the current node, even if it's not actually
+// a leaf.
+func (i *rawIterator) Path() string {
+	return i.path
+}
+
+// Next advances the iterator to the next node.
+func (i *rawIterator) Next() {
+	// Initialize our stack if needed.
+	if i.stack == nil && i.node != nil {
+		i.stack = []rawStackEntry{
+			rawStackEntry{
+				edges: edges{
+					edge{node: i.node},
+				},
+			},
+		}
+	}
+
+	for len(i.stack) > 0 {
+		// Inspect the last element of the stack.
+		n := len(i.stack)
+		last := i.stack[n-1]
+		elem := last.edges[0].node
+
+		// Update the stack.
+		if len(last.edges) > 1 {
+			i.stack[n-1].edges = last.edges[1:]
+		} else {
+			i.stack = i.stack[:n-1]
+		}
+
+		// Push the edges onto the frontier.
+		if len(elem.edges) > 0 {
+			path := last.path + string(elem.prefix)
+			i.stack = append(i.stack, rawStackEntry{path, elem.edges})
+		}
+
+		i.pos = elem
+		i.path = last.path + string(elem.prefix)
+		return
+	}
+
+	i.pos = nil
+	i.path = ""
+}