diff --git a/vendor/github.com/cespare/xxhash/README.md b/vendor/github.com/cespare/xxhash/README.md
deleted file mode 100644
index 0982fd2..0000000
--- a/vendor/github.com/cespare/xxhash/README.md
+++ /dev/null
@@ -1,50 +0,0 @@
-# xxhash
-
-[![GoDoc](https://godoc.org/github.com/cespare/xxhash?status.svg)](https://godoc.org/github.com/cespare/xxhash)
-
-xxhash is a Go implementation of the 64-bit
-[xxHash](http://cyan4973.github.io/xxHash/) algorithm, XXH64. This is a
-high-quality hashing algorithm that is much faster than anything in the Go
-standard library.
-
-The API is very small, taking its cue from the other hashing packages in the
-standard library:
-
-    $ go doc github.com/cespare/xxhash                                                                                                                                                                                              !
-    package xxhash // import "github.com/cespare/xxhash"
-
-    Package xxhash implements the 64-bit variant of xxHash (XXH64) as described
-    at http://cyan4973.github.io/xxHash/.
-
-    func New() hash.Hash64
-    func Sum64(b []byte) uint64
-    func Sum64String(s string) uint64
-
-This implementation provides a fast pure-Go implementation and an even faster
-assembly implementation for amd64.
-
-## Benchmarks
-
-Here are some quick benchmarks comparing the pure-Go and assembly
-implementations of Sum64 against another popular Go XXH64 implementation,
-[github.com/OneOfOne/xxhash](https://github.com/OneOfOne/xxhash):
-
-| input size | OneOfOne | cespare (purego) | cespare |
-| --- | --- | --- | --- |
-| 5 B   |  416 MB/s | 720 MB/s |  872 MB/s  |
-| 100 B | 3980 MB/s | 5013 MB/s | 5252 MB/s  |
-| 4 KB  | 12727 MB/s | 12999 MB/s | 13026 MB/s |
-| 10 MB | 9879 MB/s | 10775 MB/s | 10913 MB/s  |
-
-These numbers were generated with:
-
-```
-$ go test -benchtime 10s -bench '/OneOfOne,'
-$ go test -tags purego -benchtime 10s -bench '/xxhash,'
-$ go test -benchtime 10s -bench '/xxhash,'
-```
-
-## Projects using this package
-
-- [InfluxDB](https://github.com/influxdata/influxdb)
-- [Prometheus](https://github.com/prometheus/prometheus)
diff --git a/vendor/github.com/cespare/xxhash/go.mod b/vendor/github.com/cespare/xxhash/go.mod
deleted file mode 100644
index 10605a6..0000000
--- a/vendor/github.com/cespare/xxhash/go.mod
+++ /dev/null
@@ -1,6 +0,0 @@
-module github.com/cespare/xxhash
-
-require (
-	github.com/OneOfOne/xxhash v1.2.2
-	github.com/spaolacci/murmur3 v0.0.0-20180118202830-f09979ecbc72
-)
diff --git a/vendor/github.com/cespare/xxhash/go.sum b/vendor/github.com/cespare/xxhash/go.sum
deleted file mode 100644
index f6b5542..0000000
--- a/vendor/github.com/cespare/xxhash/go.sum
+++ /dev/null
@@ -1,4 +0,0 @@
-github.com/OneOfOne/xxhash v1.2.2 h1:KMrpdQIwFcEqXDklaen+P1axHaj9BSKzvpUUfnHldSE=
-github.com/OneOfOne/xxhash v1.2.2/go.mod h1:HSdplMjZKSmBqAxg5vPj2TmRDmfkzw+cTzAElWljhcU=
-github.com/spaolacci/murmur3 v0.0.0-20180118202830-f09979ecbc72 h1:qLC7fQah7D6K1B0ujays3HV9gkFtllcxhzImRR7ArPQ=
-github.com/spaolacci/murmur3 v0.0.0-20180118202830-f09979ecbc72/go.mod h1:JwIasOWyU6f++ZhiEuf87xNszmSA2myDM2Kzu9HwQUA=
diff --git a/vendor/github.com/cespare/xxhash/rotate.go b/vendor/github.com/cespare/xxhash/rotate.go
deleted file mode 100644
index f3eac5e..0000000
--- a/vendor/github.com/cespare/xxhash/rotate.go
+++ /dev/null
@@ -1,14 +0,0 @@
-// +build !go1.9
-
-package xxhash
-
-// TODO(caleb): After Go 1.10 comes out, remove this fallback code.
-
-func rol1(x uint64) uint64  { return (x << 1) | (x >> (64 - 1)) }
-func rol7(x uint64) uint64  { return (x << 7) | (x >> (64 - 7)) }
-func rol11(x uint64) uint64 { return (x << 11) | (x >> (64 - 11)) }
-func rol12(x uint64) uint64 { return (x << 12) | (x >> (64 - 12)) }
-func rol18(x uint64) uint64 { return (x << 18) | (x >> (64 - 18)) }
-func rol23(x uint64) uint64 { return (x << 23) | (x >> (64 - 23)) }
-func rol27(x uint64) uint64 { return (x << 27) | (x >> (64 - 27)) }
-func rol31(x uint64) uint64 { return (x << 31) | (x >> (64 - 31)) }
diff --git a/vendor/github.com/cespare/xxhash/rotate19.go b/vendor/github.com/cespare/xxhash/rotate19.go
deleted file mode 100644
index b99612b..0000000
--- a/vendor/github.com/cespare/xxhash/rotate19.go
+++ /dev/null
@@ -1,14 +0,0 @@
-// +build go1.9
-
-package xxhash
-
-import "math/bits"
-
-func rol1(x uint64) uint64  { return bits.RotateLeft64(x, 1) }
-func rol7(x uint64) uint64  { return bits.RotateLeft64(x, 7) }
-func rol11(x uint64) uint64 { return bits.RotateLeft64(x, 11) }
-func rol12(x uint64) uint64 { return bits.RotateLeft64(x, 12) }
-func rol18(x uint64) uint64 { return bits.RotateLeft64(x, 18) }
-func rol23(x uint64) uint64 { return bits.RotateLeft64(x, 23) }
-func rol27(x uint64) uint64 { return bits.RotateLeft64(x, 27) }
-func rol31(x uint64) uint64 { return bits.RotateLeft64(x, 31) }
diff --git a/vendor/github.com/cespare/xxhash/v2/.travis.yml b/vendor/github.com/cespare/xxhash/v2/.travis.yml
new file mode 100644
index 0000000..c516ea8
--- /dev/null
+++ b/vendor/github.com/cespare/xxhash/v2/.travis.yml
@@ -0,0 +1,8 @@
+language: go
+go:
+  - "1.x"
+  - master
+env:
+  - TAGS=""
+  - TAGS="-tags purego"
+script: go test $TAGS -v ./...
diff --git a/vendor/github.com/cespare/xxhash/LICENSE.txt b/vendor/github.com/cespare/xxhash/v2/LICENSE.txt
similarity index 100%
rename from vendor/github.com/cespare/xxhash/LICENSE.txt
rename to vendor/github.com/cespare/xxhash/v2/LICENSE.txt
diff --git a/vendor/github.com/cespare/xxhash/v2/README.md b/vendor/github.com/cespare/xxhash/v2/README.md
new file mode 100644
index 0000000..2fd8693
--- /dev/null
+++ b/vendor/github.com/cespare/xxhash/v2/README.md
@@ -0,0 +1,67 @@
+# xxhash
+
+[![GoDoc](https://godoc.org/github.com/cespare/xxhash?status.svg)](https://godoc.org/github.com/cespare/xxhash)
+[![Build Status](https://travis-ci.org/cespare/xxhash.svg?branch=master)](https://travis-ci.org/cespare/xxhash)
+
+xxhash is a Go implementation of the 64-bit
+[xxHash](http://cyan4973.github.io/xxHash/) algorithm, XXH64. This is a
+high-quality hashing algorithm that is much faster than anything in the Go
+standard library.
+
+This package provides a straightforward API:
+
+```
+func Sum64(b []byte) uint64
+func Sum64String(s string) uint64
+type Digest struct{ ... }
+    func New() *Digest
+```
+
+The `Digest` type implements hash.Hash64. Its key methods are:
+
+```
+func (*Digest) Write([]byte) (int, error)
+func (*Digest) WriteString(string) (int, error)
+func (*Digest) Sum64() uint64
+```
+
+This implementation provides a fast pure-Go implementation and an even faster
+assembly implementation for amd64.
+
+## Compatibility
+
+This package is in a module and the latest code is in version 2 of the module.
+You need a version of Go with at least "minimal module compatibility" to use
+github.com/cespare/xxhash/v2:
+
+* 1.9.7+ for Go 1.9
+* 1.10.3+ for Go 1.10
+* Go 1.11 or later
+
+I recommend using the latest release of Go.
+
+## Benchmarks
+
+Here are some quick benchmarks comparing the pure-Go and assembly
+implementations of Sum64.
+
+| input size | purego | asm |
+| --- | --- | --- |
+| 5 B   |  979.66 MB/s |  1291.17 MB/s  |
+| 100 B | 7475.26 MB/s | 7973.40 MB/s  |
+| 4 KB  | 17573.46 MB/s | 17602.65 MB/s |
+| 10 MB | 17131.46 MB/s | 17142.16 MB/s |
+
+These numbers were generated on Ubuntu 18.04 with an Intel i7-8700K CPU using
+the following commands under Go 1.11.2:
+
+```
+$ go test -tags purego -benchtime 10s -bench '/xxhash,direct,bytes'
+$ go test -benchtime 10s -bench '/xxhash,direct,bytes'
+```
+
+## Projects using this package
+
+- [InfluxDB](https://github.com/influxdata/influxdb)
+- [Prometheus](https://github.com/prometheus/prometheus)
+- [FreeCache](https://github.com/coocood/freecache)
diff --git a/vendor/github.com/cespare/xxhash/v2/go.mod b/vendor/github.com/cespare/xxhash/v2/go.mod
new file mode 100644
index 0000000..49f6760
--- /dev/null
+++ b/vendor/github.com/cespare/xxhash/v2/go.mod
@@ -0,0 +1,3 @@
+module github.com/cespare/xxhash/v2
+
+go 1.11
diff --git a/vendor/github.com/cespare/xxhash/v2/go.sum b/vendor/github.com/cespare/xxhash/v2/go.sum
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/vendor/github.com/cespare/xxhash/v2/go.sum
diff --git a/vendor/github.com/cespare/xxhash/v2/xxhash.go b/vendor/github.com/cespare/xxhash/v2/xxhash.go
new file mode 100644
index 0000000..db0b35f
--- /dev/null
+++ b/vendor/github.com/cespare/xxhash/v2/xxhash.go
@@ -0,0 +1,236 @@
+// Package xxhash implements the 64-bit variant of xxHash (XXH64) as described
+// at http://cyan4973.github.io/xxHash/.
+package xxhash
+
+import (
+	"encoding/binary"
+	"errors"
+	"math/bits"
+)
+
+const (
+	prime1 uint64 = 11400714785074694791
+	prime2 uint64 = 14029467366897019727
+	prime3 uint64 = 1609587929392839161
+	prime4 uint64 = 9650029242287828579
+	prime5 uint64 = 2870177450012600261
+)
+
+// NOTE(caleb): I'm using both consts and vars of the primes. Using consts where
+// possible in the Go code is worth a small (but measurable) performance boost
+// by avoiding some MOVQs. Vars are needed for the asm and also are useful for
+// convenience in the Go code in a few places where we need to intentionally
+// avoid constant arithmetic (e.g., v1 := prime1 + prime2 fails because the
+// result overflows a uint64).
+var (
+	prime1v = prime1
+	prime2v = prime2
+	prime3v = prime3
+	prime4v = prime4
+	prime5v = prime5
+)
+
+// Digest implements hash.Hash64.
+type Digest struct {
+	v1    uint64
+	v2    uint64
+	v3    uint64
+	v4    uint64
+	total uint64
+	mem   [32]byte
+	n     int // how much of mem is used
+}
+
+// New creates a new Digest that computes the 64-bit xxHash algorithm.
+func New() *Digest {
+	var d Digest
+	d.Reset()
+	return &d
+}
+
+// Reset clears the Digest's state so that it can be reused.
+func (d *Digest) Reset() {
+	d.v1 = prime1v + prime2
+	d.v2 = prime2
+	d.v3 = 0
+	d.v4 = -prime1v
+	d.total = 0
+	d.n = 0
+}
+
+// Size always returns 8 bytes.
+func (d *Digest) Size() int { return 8 }
+
+// BlockSize always returns 32 bytes.
+func (d *Digest) BlockSize() int { return 32 }
+
+// Write adds more data to d. It always returns len(b), nil.
+func (d *Digest) Write(b []byte) (n int, err error) {
+	n = len(b)
+	d.total += uint64(n)
+
+	if d.n+n < 32 {
+		// This new data doesn't even fill the current block.
+		copy(d.mem[d.n:], b)
+		d.n += n
+		return
+	}
+
+	if d.n > 0 {
+		// Finish off the partial block.
+		copy(d.mem[d.n:], b)
+		d.v1 = round(d.v1, u64(d.mem[0:8]))
+		d.v2 = round(d.v2, u64(d.mem[8:16]))
+		d.v3 = round(d.v3, u64(d.mem[16:24]))
+		d.v4 = round(d.v4, u64(d.mem[24:32]))
+		b = b[32-d.n:]
+		d.n = 0
+	}
+
+	if len(b) >= 32 {
+		// One or more full blocks left.
+		nw := writeBlocks(d, b)
+		b = b[nw:]
+	}
+
+	// Store any remaining partial block.
+	copy(d.mem[:], b)
+	d.n = len(b)
+
+	return
+}
+
+// Sum appends the current hash to b and returns the resulting slice.
+func (d *Digest) Sum(b []byte) []byte {
+	s := d.Sum64()
+	return append(
+		b,
+		byte(s>>56),
+		byte(s>>48),
+		byte(s>>40),
+		byte(s>>32),
+		byte(s>>24),
+		byte(s>>16),
+		byte(s>>8),
+		byte(s),
+	)
+}
+
+// Sum64 returns the current hash.
+func (d *Digest) Sum64() uint64 {
+	var h uint64
+
+	if d.total >= 32 {
+		v1, v2, v3, v4 := d.v1, d.v2, d.v3, d.v4
+		h = rol1(v1) + rol7(v2) + rol12(v3) + rol18(v4)
+		h = mergeRound(h, v1)
+		h = mergeRound(h, v2)
+		h = mergeRound(h, v3)
+		h = mergeRound(h, v4)
+	} else {
+		h = d.v3 + prime5
+	}
+
+	h += d.total
+
+	i, end := 0, d.n
+	for ; i+8 <= end; i += 8 {
+		k1 := round(0, u64(d.mem[i:i+8]))
+		h ^= k1
+		h = rol27(h)*prime1 + prime4
+	}
+	if i+4 <= end {
+		h ^= uint64(u32(d.mem[i:i+4])) * prime1
+		h = rol23(h)*prime2 + prime3
+		i += 4
+	}
+	for i < end {
+		h ^= uint64(d.mem[i]) * prime5
+		h = rol11(h) * prime1
+		i++
+	}
+
+	h ^= h >> 33
+	h *= prime2
+	h ^= h >> 29
+	h *= prime3
+	h ^= h >> 32
+
+	return h
+}
+
+const (
+	magic         = "xxh\x06"
+	marshaledSize = len(magic) + 8*5 + 32
+)
+
+// MarshalBinary implements the encoding.BinaryMarshaler interface.
+func (d *Digest) MarshalBinary() ([]byte, error) {
+	b := make([]byte, 0, marshaledSize)
+	b = append(b, magic...)
+	b = appendUint64(b, d.v1)
+	b = appendUint64(b, d.v2)
+	b = appendUint64(b, d.v3)
+	b = appendUint64(b, d.v4)
+	b = appendUint64(b, d.total)
+	b = append(b, d.mem[:d.n]...)
+	b = b[:len(b)+len(d.mem)-d.n]
+	return b, nil
+}
+
+// UnmarshalBinary implements the encoding.BinaryUnmarshaler interface.
+func (d *Digest) UnmarshalBinary(b []byte) error {
+	if len(b) < len(magic) || string(b[:len(magic)]) != magic {
+		return errors.New("xxhash: invalid hash state identifier")
+	}
+	if len(b) != marshaledSize {
+		return errors.New("xxhash: invalid hash state size")
+	}
+	b = b[len(magic):]
+	b, d.v1 = consumeUint64(b)
+	b, d.v2 = consumeUint64(b)
+	b, d.v3 = consumeUint64(b)
+	b, d.v4 = consumeUint64(b)
+	b, d.total = consumeUint64(b)
+	copy(d.mem[:], b)
+	b = b[len(d.mem):]
+	d.n = int(d.total % uint64(len(d.mem)))
+	return nil
+}
+
+func appendUint64(b []byte, x uint64) []byte {
+	var a [8]byte
+	binary.LittleEndian.PutUint64(a[:], x)
+	return append(b, a[:]...)
+}
+
+func consumeUint64(b []byte) ([]byte, uint64) {
+	x := u64(b)
+	return b[8:], x
+}
+
+func u64(b []byte) uint64 { return binary.LittleEndian.Uint64(b) }
+func u32(b []byte) uint32 { return binary.LittleEndian.Uint32(b) }
+
+func round(acc, input uint64) uint64 {
+	acc += input * prime2
+	acc = rol31(acc)
+	acc *= prime1
+	return acc
+}
+
+func mergeRound(acc, val uint64) uint64 {
+	val = round(0, val)
+	acc ^= val
+	acc = acc*prime1 + prime4
+	return acc
+}
+
+func rol1(x uint64) uint64  { return bits.RotateLeft64(x, 1) }
+func rol7(x uint64) uint64  { return bits.RotateLeft64(x, 7) }
+func rol11(x uint64) uint64 { return bits.RotateLeft64(x, 11) }
+func rol12(x uint64) uint64 { return bits.RotateLeft64(x, 12) }
+func rol18(x uint64) uint64 { return bits.RotateLeft64(x, 18) }
+func rol23(x uint64) uint64 { return bits.RotateLeft64(x, 23) }
+func rol27(x uint64) uint64 { return bits.RotateLeft64(x, 27) }
+func rol31(x uint64) uint64 { return bits.RotateLeft64(x, 31) }
diff --git a/vendor/github.com/cespare/xxhash/xxhash_amd64.go b/vendor/github.com/cespare/xxhash/v2/xxhash_amd64.go
similarity index 74%
rename from vendor/github.com/cespare/xxhash/xxhash_amd64.go
rename to vendor/github.com/cespare/xxhash/v2/xxhash_amd64.go
index d617652..ad14b80 100644
--- a/vendor/github.com/cespare/xxhash/xxhash_amd64.go
+++ b/vendor/github.com/cespare/xxhash/v2/xxhash_amd64.go
@@ -9,4 +9,5 @@
 //go:noescape
 func Sum64(b []byte) uint64
 
-func writeBlocks(x *xxh, b []byte) []byte
+//go:noescape
+func writeBlocks(d *Digest, b []byte) int
diff --git a/vendor/github.com/cespare/xxhash/xxhash_amd64.s b/vendor/github.com/cespare/xxhash/v2/xxhash_amd64.s
similarity index 78%
rename from vendor/github.com/cespare/xxhash/xxhash_amd64.s
rename to vendor/github.com/cespare/xxhash/v2/xxhash_amd64.s
index 757f201..d580e32 100644
--- a/vendor/github.com/cespare/xxhash/xxhash_amd64.s
+++ b/vendor/github.com/cespare/xxhash/v2/xxhash_amd64.s
@@ -170,23 +170,22 @@
 	RET
 
 // writeBlocks uses the same registers as above except that it uses AX to store
-// the x pointer.
+// the d pointer.
 
-// func writeBlocks(x *xxh, b []byte) []byte
-TEXT ·writeBlocks(SB), NOSPLIT, $0-56
+// func writeBlocks(d *Digest, b []byte) int
+TEXT ·writeBlocks(SB), NOSPLIT, $0-40
 	// Load fixed primes needed for round.
 	MOVQ ·prime1v(SB), R13
 	MOVQ ·prime2v(SB), R14
 
 	// Load slice.
 	MOVQ b_base+8(FP), CX
-	MOVQ CX, ret_base+32(FP) // initialize return base pointer; see NOTE below
 	MOVQ b_len+16(FP), DX
 	LEAQ (CX)(DX*1), BX
 	SUBQ $32, BX
 
-	// Load vN from x.
-	MOVQ x+0(FP), AX
+	// Load vN from d.
+	MOVQ d+0(FP), AX
 	MOVQ 0(AX), R8   // v1
 	MOVQ 8(AX), R9   // v2
 	MOVQ 16(AX), R10 // v3
@@ -203,31 +202,14 @@
 	CMPQ CX, BX
 	JLE  blockLoop
 
-	// Copy vN back to x.
+	// Copy vN back to d.
 	MOVQ R8, 0(AX)
 	MOVQ R9, 8(AX)
 	MOVQ R10, 16(AX)
 	MOVQ R11, 24(AX)
 
-	// Construct return slice.
-	// NOTE: It's important that we don't construct a slice that has a base
-	// pointer off the end of the original slice, as in Go 1.7+ this will
-	// cause runtime crashes. (See discussion in, for example,
-	// https://github.com/golang/go/issues/16772.)
-	// Therefore, we calculate the length/cap first, and if they're zero, we
-	// keep the old base. This is what the compiler does as well if you
-	// write code like
-	//   b = b[len(b):]
-
-	// New length is 32 - (CX - BX) -> BX+32 - CX.
-	ADDQ $32, BX
-	SUBQ CX, BX
-	JZ   afterSetBase
-
-	MOVQ CX, ret_base+32(FP)
-
-afterSetBase:
-	MOVQ BX, ret_len+40(FP)
-	MOVQ BX, ret_cap+48(FP) // set cap == len
+	// The number of bytes written is CX minus the old base pointer.
+	SUBQ b_base+8(FP), CX
+	MOVQ CX, ret+32(FP)
 
 	RET
diff --git a/vendor/github.com/cespare/xxhash/xxhash_other.go b/vendor/github.com/cespare/xxhash/v2/xxhash_other.go
similarity index 85%
rename from vendor/github.com/cespare/xxhash/xxhash_other.go
rename to vendor/github.com/cespare/xxhash/v2/xxhash_other.go
index c68d13f..4a5a821 100644
--- a/vendor/github.com/cespare/xxhash/xxhash_other.go
+++ b/vendor/github.com/cespare/xxhash/v2/xxhash_other.go
@@ -5,9 +5,9 @@
 // Sum64 computes the 64-bit xxHash digest of b.
 func Sum64(b []byte) uint64 {
 	// A simpler version would be
-	//   x := New()
-	//   x.Write(b)
-	//   return x.Sum64()
+	//   d := New()
+	//   d.Write(b)
+	//   return d.Sum64()
 	// but this is faster, particularly for small inputs.
 
 	n := len(b)
@@ -61,8 +61,9 @@
 	return h
 }
 
-func writeBlocks(x *xxh, b []byte) []byte {
-	v1, v2, v3, v4 := x.v1, x.v2, x.v3, x.v4
+func writeBlocks(d *Digest, b []byte) int {
+	v1, v2, v3, v4 := d.v1, d.v2, d.v3, d.v4
+	n := len(b)
 	for len(b) >= 32 {
 		v1 = round(v1, u64(b[0:8:len(b)]))
 		v2 = round(v2, u64(b[8:16:len(b)]))
@@ -70,6 +71,6 @@
 		v4 = round(v4, u64(b[24:32:len(b)]))
 		b = b[32:len(b):len(b)]
 	}
-	x.v1, x.v2, x.v3, x.v4 = v1, v2, v3, v4
-	return b
+	d.v1, d.v2, d.v3, d.v4 = v1, v2, v3, v4
+	return n - len(b)
 }
diff --git a/vendor/github.com/cespare/xxhash/xxhash_safe.go b/vendor/github.com/cespare/xxhash/v2/xxhash_safe.go
similarity index 60%
rename from vendor/github.com/cespare/xxhash/xxhash_safe.go
rename to vendor/github.com/cespare/xxhash/v2/xxhash_safe.go
index dfa15ab..fc9bea7 100644
--- a/vendor/github.com/cespare/xxhash/xxhash_safe.go
+++ b/vendor/github.com/cespare/xxhash/v2/xxhash_safe.go
@@ -8,3 +8,8 @@
 func Sum64String(s string) uint64 {
 	return Sum64([]byte(s))
 }
+
+// WriteString adds more data to d. It always returns len(s), nil.
+func (d *Digest) WriteString(s string) (n int, err error) {
+	return d.Write([]byte(s))
+}
diff --git a/vendor/github.com/cespare/xxhash/v2/xxhash_unsafe.go b/vendor/github.com/cespare/xxhash/v2/xxhash_unsafe.go
new file mode 100644
index 0000000..53bf76e
--- /dev/null
+++ b/vendor/github.com/cespare/xxhash/v2/xxhash_unsafe.go
@@ -0,0 +1,46 @@
+// +build !appengine
+
+// This file encapsulates usage of unsafe.
+// xxhash_safe.go contains the safe implementations.
+
+package xxhash
+
+import (
+	"reflect"
+	"unsafe"
+)
+
+// Notes:
+//
+// See https://groups.google.com/d/msg/golang-nuts/dcjzJy-bSpw/tcZYBzQqAQAJ
+// for some discussion about these unsafe conversions.
+//
+// In the future it's possible that compiler optimizations will make these
+// unsafe operations unnecessary: https://golang.org/issue/2205.
+//
+// Both of these wrapper functions still incur function call overhead since they
+// will not be inlined. We could write Go/asm copies of Sum64 and Digest.Write
+// for strings to squeeze out a bit more speed. Mid-stack inlining should
+// eventually fix this.
+
+// Sum64String computes the 64-bit xxHash digest of s.
+// It may be faster than Sum64([]byte(s)) by avoiding a copy.
+func Sum64String(s string) uint64 {
+	var b []byte
+	bh := (*reflect.SliceHeader)(unsafe.Pointer(&b))
+	bh.Data = (*reflect.StringHeader)(unsafe.Pointer(&s)).Data
+	bh.Len = len(s)
+	bh.Cap = len(s)
+	return Sum64(b)
+}
+
+// WriteString adds more data to d. It always returns len(s), nil.
+// It may be faster than Write([]byte(s)) by avoiding a copy.
+func (d *Digest) WriteString(s string) (n int, err error) {
+	var b []byte
+	bh := (*reflect.SliceHeader)(unsafe.Pointer(&b))
+	bh.Data = (*reflect.StringHeader)(unsafe.Pointer(&s)).Data
+	bh.Len = len(s)
+	bh.Cap = len(s)
+	return d.Write(b)
+}
diff --git a/vendor/github.com/cespare/xxhash/xxhash.go b/vendor/github.com/cespare/xxhash/xxhash.go
deleted file mode 100644
index f896bd2..0000000
--- a/vendor/github.com/cespare/xxhash/xxhash.go
+++ /dev/null
@@ -1,168 +0,0 @@
-// Package xxhash implements the 64-bit variant of xxHash (XXH64) as described
-// at http://cyan4973.github.io/xxHash/.
-package xxhash
-
-import (
-	"encoding/binary"
-	"hash"
-)
-
-const (
-	prime1 uint64 = 11400714785074694791
-	prime2 uint64 = 14029467366897019727
-	prime3 uint64 = 1609587929392839161
-	prime4 uint64 = 9650029242287828579
-	prime5 uint64 = 2870177450012600261
-)
-
-// NOTE(caleb): I'm using both consts and vars of the primes. Using consts where
-// possible in the Go code is worth a small (but measurable) performance boost
-// by avoiding some MOVQs. Vars are needed for the asm and also are useful for
-// convenience in the Go code in a few places where we need to intentionally
-// avoid constant arithmetic (e.g., v1 := prime1 + prime2 fails because the
-// result overflows a uint64).
-var (
-	prime1v = prime1
-	prime2v = prime2
-	prime3v = prime3
-	prime4v = prime4
-	prime5v = prime5
-)
-
-type xxh struct {
-	v1    uint64
-	v2    uint64
-	v3    uint64
-	v4    uint64
-	total int
-	mem   [32]byte
-	n     int // how much of mem is used
-}
-
-// New creates a new hash.Hash64 that implements the 64-bit xxHash algorithm.
-func New() hash.Hash64 {
-	var x xxh
-	x.Reset()
-	return &x
-}
-
-func (x *xxh) Reset() {
-	x.n = 0
-	x.total = 0
-	x.v1 = prime1v + prime2
-	x.v2 = prime2
-	x.v3 = 0
-	x.v4 = -prime1v
-}
-
-func (x *xxh) Size() int      { return 8 }
-func (x *xxh) BlockSize() int { return 32 }
-
-// Write adds more data to x. It always returns len(b), nil.
-func (x *xxh) Write(b []byte) (n int, err error) {
-	n = len(b)
-	x.total += len(b)
-
-	if x.n+len(b) < 32 {
-		// This new data doesn't even fill the current block.
-		copy(x.mem[x.n:], b)
-		x.n += len(b)
-		return
-	}
-
-	if x.n > 0 {
-		// Finish off the partial block.
-		copy(x.mem[x.n:], b)
-		x.v1 = round(x.v1, u64(x.mem[0:8]))
-		x.v2 = round(x.v2, u64(x.mem[8:16]))
-		x.v3 = round(x.v3, u64(x.mem[16:24]))
-		x.v4 = round(x.v4, u64(x.mem[24:32]))
-		b = b[32-x.n:]
-		x.n = 0
-	}
-
-	if len(b) >= 32 {
-		// One or more full blocks left.
-		b = writeBlocks(x, b)
-	}
-
-	// Store any remaining partial block.
-	copy(x.mem[:], b)
-	x.n = len(b)
-
-	return
-}
-
-func (x *xxh) Sum(b []byte) []byte {
-	s := x.Sum64()
-	return append(
-		b,
-		byte(s>>56),
-		byte(s>>48),
-		byte(s>>40),
-		byte(s>>32),
-		byte(s>>24),
-		byte(s>>16),
-		byte(s>>8),
-		byte(s),
-	)
-}
-
-func (x *xxh) Sum64() uint64 {
-	var h uint64
-
-	if x.total >= 32 {
-		v1, v2, v3, v4 := x.v1, x.v2, x.v3, x.v4
-		h = rol1(v1) + rol7(v2) + rol12(v3) + rol18(v4)
-		h = mergeRound(h, v1)
-		h = mergeRound(h, v2)
-		h = mergeRound(h, v3)
-		h = mergeRound(h, v4)
-	} else {
-		h = x.v3 + prime5
-	}
-
-	h += uint64(x.total)
-
-	i, end := 0, x.n
-	for ; i+8 <= end; i += 8 {
-		k1 := round(0, u64(x.mem[i:i+8]))
-		h ^= k1
-		h = rol27(h)*prime1 + prime4
-	}
-	if i+4 <= end {
-		h ^= uint64(u32(x.mem[i:i+4])) * prime1
-		h = rol23(h)*prime2 + prime3
-		i += 4
-	}
-	for i < end {
-		h ^= uint64(x.mem[i]) * prime5
-		h = rol11(h) * prime1
-		i++
-	}
-
-	h ^= h >> 33
-	h *= prime2
-	h ^= h >> 29
-	h *= prime3
-	h ^= h >> 32
-
-	return h
-}
-
-func u64(b []byte) uint64 { return binary.LittleEndian.Uint64(b) }
-func u32(b []byte) uint32 { return binary.LittleEndian.Uint32(b) }
-
-func round(acc, input uint64) uint64 {
-	acc += input * prime2
-	acc = rol31(acc)
-	acc *= prime1
-	return acc
-}
-
-func mergeRound(acc, val uint64) uint64 {
-	val = round(0, val)
-	acc ^= val
-	acc = acc*prime1 + prime4
-	return acc
-}
diff --git a/vendor/github.com/cespare/xxhash/xxhash_unsafe.go b/vendor/github.com/cespare/xxhash/xxhash_unsafe.go
deleted file mode 100644
index d2b64e8..0000000
--- a/vendor/github.com/cespare/xxhash/xxhash_unsafe.go
+++ /dev/null
@@ -1,30 +0,0 @@
-// +build !appengine
-
-// This file encapsulates usage of unsafe.
-// xxhash_safe.go contains the safe implementations.
-
-package xxhash
-
-import (
-	"reflect"
-	"unsafe"
-)
-
-// Sum64String computes the 64-bit xxHash digest of s.
-// It may be faster than Sum64([]byte(s)) by avoiding a copy.
-//
-// TODO(caleb): Consider removing this if an optimization is ever added to make
-// it unnecessary: https://golang.org/issue/2205.
-//
-// TODO(caleb): We still have a function call; we could instead write Go/asm
-// copies of Sum64 for strings to squeeze out a bit more speed.
-func Sum64String(s string) uint64 {
-	// See https://groups.google.com/d/msg/golang-nuts/dcjzJy-bSpw/tcZYBzQqAQAJ
-	// for some discussion about this unsafe conversion.
-	var b []byte
-	bh := (*reflect.SliceHeader)(unsafe.Pointer(&b))
-	bh.Data = (*reflect.StringHeader)(unsafe.Pointer(&s)).Data
-	bh.Len = len(s)
-	bh.Cap = len(s)
-	return Sum64(b)
-}