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
+}