diff --git a/vendor/github.com/pierrec/lz4/.gitignore b/vendor/github.com/pierrec/lz4/.gitignore
index e48bab3..5e98735 100644
--- a/vendor/github.com/pierrec/lz4/.gitignore
+++ b/vendor/github.com/pierrec/lz4/.gitignore
@@ -30,4 +30,5 @@
 
 # End of https://www.gitignore.io/api/macos
 
-lz4c/lz4c
+cmd/*/*exe
+.idea
\ No newline at end of file
diff --git a/vendor/github.com/pierrec/lz4/.travis.yml b/vendor/github.com/pierrec/lz4/.travis.yml
index 658910d..fd6c6db 100644
--- a/vendor/github.com/pierrec/lz4/.travis.yml
+++ b/vendor/github.com/pierrec/lz4/.travis.yml
@@ -2,12 +2,12 @@
 
 env:
   - GO111MODULE=off
-  - GO111MODULE=on
 
 go:
   - 1.9.x
   - 1.10.x
   - 1.11.x
+  - 1.12.x
   - master
 
 matrix:
diff --git a/vendor/github.com/pierrec/lz4/README.md b/vendor/github.com/pierrec/lz4/README.md
index 50a10ee..4ee388e 100644
--- a/vendor/github.com/pierrec/lz4/README.md
+++ b/vendor/github.com/pierrec/lz4/README.md
@@ -1,24 +1,90 @@
-[![godoc](https://godoc.org/github.com/pierrec/lz4?status.png)](https://godoc.org/github.com/pierrec/lz4)
+# lz4 : LZ4 compression in pure Go
 
-# lz4
-LZ4 compression and decompression in pure Go.
+[![GoDoc](https://godoc.org/github.com/pierrec/lz4?status.svg)](https://godoc.org/github.com/pierrec/lz4)
+[![Build Status](https://travis-ci.org/pierrec/lz4.svg?branch=master)](https://travis-ci.org/pierrec/lz4)
+[![Go Report Card](https://goreportcard.com/badge/github.com/pierrec/lz4)](https://goreportcard.com/report/github.com/pierrec/lz4)
+[![GitHub tag (latest SemVer)](https://img.shields.io/github/tag/pierrec/lz4.svg?style=social)](https://github.com/pierrec/lz4/tags)
 
-## Usage
+## Overview
 
-```go
-import "github.com/pierrec/lz4"
+This package provides a streaming interface to [LZ4 data streams](http://fastcompression.blogspot.fr/2013/04/lz4-streaming-format-final.html) as well as low level compress and uncompress functions for LZ4 data blocks.
+The implementation is based on the reference C [one](https://github.com/lz4/lz4).
+
+## Install
+
+Assuming you have the go toolchain installed:
+
+```
+go get github.com/pierrec/lz4
 ```
 
-## Description
-Package lz4 implements reading and writing lz4 compressed data (a frame),
-as specified in http://fastcompression.blogspot.fr/2013/04/lz4-streaming-format-final.html.
+There is a command line interface tool to compress and decompress LZ4 files.
 
-This package is **compatible with the LZ4 frame format** although the block level compression 
-and decompression functions are exposed and are fully compatible with the lz4 block format 
-definition, they are low level and should not be used directly.
+```
+go install github.com/pierrec/lz4/cmd/lz4c
+```
 
-For a complete description of an lz4 compressed block, see:
-http://fastcompression.blogspot.fr/2011/05/lz4-explained.html
+Usage
 
-See https://github.com/Cyan4973/lz4 for the reference C implementation.
+```
+Usage of lz4c:
+  -version
+        print the program version
 
+Subcommands:
+Compress the given files or from stdin to stdout.
+compress [arguments] [<file name> ...]
+  -bc
+        enable block checksum
+  -l int
+        compression level (0=fastest)
+  -sc
+        disable stream checksum
+  -size string
+        block max size [64K,256K,1M,4M] (default "4M")
+
+Uncompress the given files or from stdin to stdout.
+uncompress [arguments] [<file name> ...]
+
+```
+
+
+## Example
+
+```
+// Compress and uncompress an input string.
+s := "hello world"
+r := strings.NewReader(s)
+
+// The pipe will uncompress the data from the writer.
+pr, pw := io.Pipe()
+zw := lz4.NewWriter(pw)
+zr := lz4.NewReader(pr)
+
+go func() {
+	// Compress the input string.
+	_, _ = io.Copy(zw, r)
+	_ = zw.Close() // Make sure the writer is closed
+	_ = pw.Close() // Terminate the pipe
+}()
+
+_, _ = io.Copy(os.Stdout, zr)
+
+// Output:
+// hello world
+```
+
+## Contributing
+
+Contributions are very welcome for bug fixing, performance improvements...!
+
+- Open an issue with a proper description
+- Send a pull request with appropriate test case(s)
+
+## Contributors
+
+Thanks to all [contributors](https://github.com/pierrec/lz4/graphs/contributors)  so far!
+
+Special thanks to [@Zariel](https://github.com/Zariel) for his asm implementation of the decoder.
+
+Special thanks to [@klauspost](https://github.com/klauspost) for his work on optimizing the code.
diff --git a/vendor/github.com/pierrec/lz4/block.go b/vendor/github.com/pierrec/lz4/block.go
index d96e0e7..664d9be 100644
--- a/vendor/github.com/pierrec/lz4/block.go
+++ b/vendor/github.com/pierrec/lz4/block.go
@@ -2,21 +2,14 @@
 
 import (
 	"encoding/binary"
-	"errors"
+	"math/bits"
+	"sync"
 )
 
-var (
-	// ErrInvalidSourceShortBuffer is returned by UncompressBlock or CompressBLock when a compressed
-	// block is corrupted or the destination buffer is not large enough for the uncompressed data.
-	ErrInvalidSourceShortBuffer = errors.New("lz4: invalid source or destination buffer too short")
-	// ErrInvalid is returned when reading an invalid LZ4 archive.
-	ErrInvalid = errors.New("lz4: bad magic number")
-)
-
-// blockHash hashes 4 bytes into a value < winSize.
-func blockHash(x uint32) uint32 {
-	const hasher uint32 = 2654435761 // Knuth multiplicative hash.
-	return x * hasher >> hashShift
+// blockHash hashes the lower 6 bytes into a value < htSize.
+func blockHash(x uint64) uint32 {
+	const prime6bytes = 227718039650203
+	return uint32(((x << (64 - 48)) * prime6bytes) >> (64 - hashLog))
 }
 
 // CompressBlockBound returns the maximum size of a given buffer of size n, when not compressible.
@@ -30,79 +23,127 @@
 // The destination buffer must be sized appropriately.
 //
 // An error is returned if the source data is invalid or the destination buffer is too small.
-func UncompressBlock(src, dst []byte) (di int, err error) {
-	sn := len(src)
-	if sn == 0 {
+func UncompressBlock(src, dst []byte) (int, error) {
+	if len(src) == 0 {
 		return 0, nil
 	}
-
-	di = decodeBlock(dst, src)
-	if di < 0 {
-		return 0, ErrInvalidSourceShortBuffer
+	if di := decodeBlock(dst, src); di >= 0 {
+		return di, nil
 	}
-	return di, nil
+	return 0, ErrInvalidSourceShortBuffer
 }
 
 // CompressBlock compresses the source buffer into the destination one.
 // This is the fast version of LZ4 compression and also the default one.
-// The size of hashTable must be at least 64Kb.
 //
-// The size of the compressed data is returned. If it is 0 and no error, then the data is incompressible.
+// The argument hashTable is scratch space for a hash table used by the
+// compressor. If provided, it should have length at least 1<<16. If it is
+// shorter (or nil), CompressBlock allocates its own hash table.
+//
+// The size of the compressed data is returned.
+//
+// If the destination buffer size is lower than CompressBlockBound and
+// the compressed size is 0 and no error, then the data is incompressible.
 //
 // An error is returned if the destination buffer is too small.
-func CompressBlock(src, dst []byte, hashTable []int) (di int, err error) {
-	defer func() {
-		if recover() != nil {
-			err = ErrInvalidSourceShortBuffer
-		}
-	}()
+func CompressBlock(src, dst []byte, hashTable []int) (_ int, err error) {
+	defer recoverBlock(&err)
 
-	sn, dn := len(src)-mfLimit, len(dst)
-	if sn <= 0 || dn == 0 {
-		return 0, nil
+	// Return 0, nil only if the destination buffer size is < CompressBlockBound.
+	isNotCompressible := len(dst) < CompressBlockBound(len(src))
+
+	// adaptSkipLog sets how quickly the compressor begins skipping blocks when data is incompressible.
+	// This significantly speeds up incompressible data and usually has very small impact on compression.
+	// bytes to skip =  1 + (bytes since last match >> adaptSkipLog)
+	const adaptSkipLog = 7
+	if len(hashTable) < htSize {
+		htIface := htPool.Get()
+		defer htPool.Put(htIface)
+		hashTable = (*(htIface).(*[htSize]int))[:]
 	}
-	var si int
+	// Prove to the compiler the table has at least htSize elements.
+	// The compiler can see that "uint32() >> hashShift" cannot be out of bounds.
+	hashTable = hashTable[:htSize]
+
+	// si: Current position of the search.
+	// anchor: Position of the current literals.
+	var si, di, anchor int
+	sn := len(src) - mfLimit
+	if sn <= 0 {
+		goto lastLiterals
+	}
 
 	// Fast scan strategy: the hash table only stores the last 4 bytes sequences.
-	// const accInit = 1 << skipStrength
-
-	anchor := si // Position of the current literals.
-	// acc := accInit // Variable step: improves performance on non-compressible data.
-
 	for si < sn {
-		// Hash the next 4 bytes (sequence)...
-		match := binary.LittleEndian.Uint32(src[si:])
+		// Hash the next 6 bytes (sequence)...
+		match := binary.LittleEndian.Uint64(src[si:])
 		h := blockHash(match)
+		h2 := blockHash(match >> 8)
 
+		// We check a match at s, s+1 and s+2 and pick the first one we get.
+		// Checking 3 only requires us to load the source one.
 		ref := hashTable[h]
+		ref2 := hashTable[h2]
 		hashTable[h] = si
-		if ref >= sn { // Invalid reference (dirty hashtable).
-			si++
-			continue
-		}
+		hashTable[h2] = si + 1
 		offset := si - ref
+
+		// If offset <= 0 we got an old entry in the hash table.
 		if offset <= 0 || offset >= winSize || // Out of window.
-			match != binary.LittleEndian.Uint32(src[ref:]) { // Hash collision on different matches.
-			// si += acc >> skipStrength
-			// acc++
-			si++
-			continue
+			uint32(match) != binary.LittleEndian.Uint32(src[ref:]) { // Hash collision on different matches.
+			// No match. Start calculating another hash.
+			// The processor can usually do this out-of-order.
+			h = blockHash(match >> 16)
+			ref = hashTable[h]
+
+			// Check the second match at si+1
+			si += 1
+			offset = si - ref2
+
+			if offset <= 0 || offset >= winSize ||
+				uint32(match>>8) != binary.LittleEndian.Uint32(src[ref2:]) {
+				// No match. Check the third match at si+2
+				si += 1
+				offset = si - ref
+				hashTable[h] = si
+
+				if offset <= 0 || offset >= winSize ||
+					uint32(match>>16) != binary.LittleEndian.Uint32(src[ref:]) {
+					// Skip one extra byte (at si+3) before we check 3 matches again.
+					si += 2 + (si-anchor)>>adaptSkipLog
+					continue
+				}
+			}
 		}
 
 		// Match found.
-		// acc = accInit
 		lLen := si - anchor // Literal length.
+		// We already matched 4 bytes.
+		mLen := 4
 
-		// Encode match length part 1.
-		si += minMatch
-		mLen := si // Match length has minMatch already.
-		// Find the longest match, first looking by batches of 8 bytes.
-		for si < sn && binary.LittleEndian.Uint64(src[si:]) == binary.LittleEndian.Uint64(src[si-offset:]) {
-			si += 8
+		// Extend backwards if we can, reducing literals.
+		tOff := si - offset - 1
+		for lLen > 0 && tOff >= 0 && src[si-1] == src[tOff] {
+			si--
+			tOff--
+			lLen--
+			mLen++
 		}
-		// Then byte by byte.
-		for si < sn && src[si] == src[si-offset] {
-			si++
+
+		// Add the match length, so we continue search at the end.
+		// Use mLen to store the offset base.
+		si, mLen = si+mLen, si+minMatch
+
+		// Find the longest match by looking by batches of 8 bytes.
+		for si+8 < sn {
+			x := binary.LittleEndian.Uint64(src[si:]) ^ binary.LittleEndian.Uint64(src[si-offset:])
+			if x == 0 {
+				si += 8
+			} else {
+				// Stop is first non-zero byte.
+				si += bits.TrailingZeros64(x) >> 3
+				break
+			}
 		}
 
 		mLen = si - mLen
@@ -145,9 +186,17 @@
 			dst[di] = byte(mLen)
 			di++
 		}
+		// Check if we can load next values.
+		if si >= sn {
+			break
+		}
+		// Hash match end-2
+		h = blockHash(binary.LittleEndian.Uint64(src[si-2:]))
+		hashTable[h] = si - 2
 	}
 
-	if anchor == 0 {
+lastLiterals:
+	if isNotCompressible && anchor == 0 {
 		// Incompressible.
 		return 0, nil
 	}
@@ -168,7 +217,7 @@
 	di++
 
 	// Write the last literals.
-	if di >= anchor {
+	if isNotCompressible && di >= anchor {
 		// Incompressible.
 		return 0, nil
 	}
@@ -176,40 +225,60 @@
 	return di, nil
 }
 
+// Pool of hash tables for CompressBlock.
+var htPool = sync.Pool{
+	New: func() interface{} {
+		return new([htSize]int)
+	},
+}
+
+// blockHash hashes 4 bytes into a value < winSize.
+func blockHashHC(x uint32) uint32 {
+	const hasher uint32 = 2654435761 // Knuth multiplicative hash.
+	return x * hasher >> (32 - winSizeLog)
+}
+
 // CompressBlockHC compresses the source buffer src into the destination dst
 // with max search depth (use 0 or negative value for no max).
 //
 // CompressBlockHC compression ratio is better than CompressBlock but it is also slower.
 //
-// The size of the compressed data is returned. If it is 0 and no error, then the data is not compressible.
+// The size of the compressed data is returned.
+//
+// If the destination buffer size is lower than CompressBlockBound and
+// the compressed size is 0 and no error, then the data is incompressible.
 //
 // An error is returned if the destination buffer is too small.
-func CompressBlockHC(src, dst []byte, depth int) (di int, err error) {
-	defer func() {
-		if recover() != nil {
-			err = ErrInvalidSourceShortBuffer
-		}
-	}()
+func CompressBlockHC(src, dst []byte, depth int) (_ int, err error) {
+	defer recoverBlock(&err)
 
-	sn, dn := len(src)-mfLimit, len(dst)
-	if sn <= 0 || dn == 0 {
-		return 0, nil
-	}
-	var si int
+	// Return 0, nil only if the destination buffer size is < CompressBlockBound.
+	isNotCompressible := len(dst) < CompressBlockBound(len(src))
+
+	// adaptSkipLog sets how quickly the compressor begins skipping blocks when data is incompressible.
+	// This significantly speeds up incompressible data and usually has very small impact on compression.
+	// bytes to skip =  1 + (bytes since last match >> adaptSkipLog)
+	const adaptSkipLog = 7
+
+	var si, di, anchor int
 
 	// hashTable: stores the last position found for a given hash
-	// chaingTable: stores previous positions for a given hash
+	// chainTable: stores previous positions for a given hash
 	var hashTable, chainTable [winSize]int
 
 	if depth <= 0 {
 		depth = winSize
 	}
 
-	anchor := si
+	sn := len(src) - mfLimit
+	if sn <= 0 {
+		goto lastLiterals
+	}
+
 	for si < sn {
 		// Hash the next 4 bytes (sequence).
 		match := binary.LittleEndian.Uint32(src[si:])
-		h := blockHash(match)
+		h := blockHashHC(match)
 
 		// Follow the chain until out of window and give the longest match.
 		mLen := 0
@@ -222,11 +291,15 @@
 			}
 			ml := 0
 			// Compare the current position with a previous with the same hash.
-			for ml < sn-si && binary.LittleEndian.Uint64(src[next+ml:]) == binary.LittleEndian.Uint64(src[si+ml:]) {
-				ml += 8
-			}
-			for ml < sn-si && src[next+ml] == src[si+ml] {
-				ml++
+			for ml < sn-si {
+				x := binary.LittleEndian.Uint64(src[next+ml:]) ^ binary.LittleEndian.Uint64(src[si+ml:])
+				if x == 0 {
+					ml += 8
+				} else {
+					// Stop is first non-zero byte.
+					ml += bits.TrailingZeros64(x) >> 3
+					break
+				}
 			}
 			if ml < minMatch || ml <= mLen {
 				// Match too small (<minMath) or smaller than the current match.
@@ -243,7 +316,7 @@
 
 		// No match found.
 		if mLen == 0 {
-			si++
+			si += 1 + (si-anchor)>>adaptSkipLog
 			continue
 		}
 
@@ -257,7 +330,7 @@
 		for si, ml := winStart, si+mLen; si < ml; {
 			match >>= 8
 			match |= uint32(src[si+3]) << 24
-			h := blockHash(match)
+			h := blockHashHC(match)
 			chainTable[si&winMask] = hashTable[h]
 			hashTable[h] = si
 			si++
@@ -308,12 +381,13 @@
 		}
 	}
 
-	if anchor == 0 {
+	if isNotCompressible && anchor == 0 {
 		// Incompressible.
 		return 0, nil
 	}
 
 	// Last literals.
+lastLiterals:
 	lLen := len(src) - anchor
 	if lLen < 0xF {
 		dst[di] = byte(lLen << 4)
@@ -330,7 +404,7 @@
 	di++
 
 	// Write the last literals.
-	if di >= anchor {
+	if isNotCompressible && di >= anchor {
 		// Incompressible.
 		return 0, nil
 	}
diff --git a/vendor/github.com/pierrec/lz4/decode_other.go b/vendor/github.com/pierrec/lz4/decode_other.go
index b83a19a..919888e 100644
--- a/vendor/github.com/pierrec/lz4/decode_other.go
+++ b/vendor/github.com/pierrec/lz4/decode_other.go
@@ -3,11 +3,10 @@
 package lz4
 
 func decodeBlock(dst, src []byte) (ret int) {
+	const hasError = -2
 	defer func() {
-		// It is now faster to let the runtime panic and recover on out of bound slice access
-		// than checking indices as we go along.
 		if recover() != nil {
-			ret = -2
+			ret = hasError
 		}
 	}()
 
@@ -20,7 +19,7 @@
 		// Literals.
 		if lLen := b >> 4; lLen > 0 {
 			switch {
-			case lLen < 0xF && di+18 < len(dst) && si+16 < len(src):
+			case lLen < 0xF && si+16 < len(src):
 				// Shortcut 1
 				// if we have enough room in src and dst, and the literals length
 				// is small enough (0..14) then copy all 16 bytes, even if not all
@@ -35,7 +34,13 @@
 					mLen += 4
 					if offset := int(src[si]) | int(src[si+1])<<8; mLen <= offset {
 						i := di - offset
-						copy(dst[di:], dst[i:i+18])
+						end := i + 18
+						if end > len(dst) {
+							// The remaining buffer may not hold 18 bytes.
+							// See https://github.com/pierrec/lz4/issues/51.
+							end = len(dst)
+						}
+						copy(dst[di:], dst[i:end])
 						si += 2
 						di += mLen
 						continue
@@ -61,7 +66,7 @@
 
 		offset := int(src[si]) | int(src[si+1])<<8
 		if offset == 0 {
-			return -2
+			return hasError
 		}
 		si += 2
 
@@ -90,6 +95,4 @@
 		}
 		di += copy(dst[di:di+mLen], expanded[:mLen])
 	}
-
-	return di
 }
diff --git a/vendor/github.com/pierrec/lz4/errors.go b/vendor/github.com/pierrec/lz4/errors.go
new file mode 100644
index 0000000..1c45d18
--- /dev/null
+++ b/vendor/github.com/pierrec/lz4/errors.go
@@ -0,0 +1,30 @@
+package lz4
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	rdebug "runtime/debug"
+)
+
+var (
+	// ErrInvalidSourceShortBuffer is returned by UncompressBlock or CompressBLock when a compressed
+	// block is corrupted or the destination buffer is not large enough for the uncompressed data.
+	ErrInvalidSourceShortBuffer = errors.New("lz4: invalid source or destination buffer too short")
+	// ErrInvalid is returned when reading an invalid LZ4 archive.
+	ErrInvalid = errors.New("lz4: bad magic number")
+	// ErrBlockDependency is returned when attempting to decompress an archive created with block dependency.
+	ErrBlockDependency = errors.New("lz4: block dependency not supported")
+	// ErrUnsupportedSeek is returned when attempting to Seek any way but forward from the current position.
+	ErrUnsupportedSeek = errors.New("lz4: can only seek forward from io.SeekCurrent")
+)
+
+func recoverBlock(e *error) {
+	if r := recover(); r != nil && *e == nil {
+		if debugFlag {
+			fmt.Fprintln(os.Stderr, r)
+			rdebug.PrintStack()
+		}
+		*e = ErrInvalidSourceShortBuffer
+	}
+}
diff --git a/vendor/github.com/pierrec/lz4/go.mod b/vendor/github.com/pierrec/lz4/go.mod
deleted file mode 100644
index f9f570a..0000000
--- a/vendor/github.com/pierrec/lz4/go.mod
+++ /dev/null
@@ -1,3 +0,0 @@
-module github.com/pierrec/lz4
-
-require github.com/pkg/profile v1.2.1
diff --git a/vendor/github.com/pierrec/lz4/go.sum b/vendor/github.com/pierrec/lz4/go.sum
deleted file mode 100644
index 6ca7598..0000000
--- a/vendor/github.com/pierrec/lz4/go.sum
+++ /dev/null
@@ -1,2 +0,0 @@
-github.com/pkg/profile v1.2.1 h1:F++O52m40owAmADcojzM+9gyjmMOY/T4oYJkgFDH8RE=
-github.com/pkg/profile v1.2.1/go.mod h1:hJw3o1OdXxsrSjjVksARp5W95eeEaEfptyVZyv6JUPA=
diff --git a/vendor/github.com/pierrec/lz4/internal/xxh32/xxh32zero.go b/vendor/github.com/pierrec/lz4/internal/xxh32/xxh32zero.go
index 850a6fd..7a76a6b 100644
--- a/vendor/github.com/pierrec/lz4/internal/xxh32/xxh32zero.go
+++ b/vendor/github.com/pierrec/lz4/internal/xxh32/xxh32zero.go
@@ -7,14 +7,15 @@
 )
 
 const (
-	prime32_1 uint32 = 2654435761
-	prime32_2 uint32 = 2246822519
-	prime32_3 uint32 = 3266489917
-	prime32_4 uint32 = 668265263
-	prime32_5 uint32 = 374761393
+	prime1 uint32 = 2654435761
+	prime2 uint32 = 2246822519
+	prime3 uint32 = 3266489917
+	prime4 uint32 = 668265263
+	prime5 uint32 = 374761393
 
-	prime32_1plus2 uint32 = 606290984
-	prime32_minus1 uint32 = 1640531535
+	primeMask   = 0xFFFFFFFF
+	prime1plus2 = uint32((uint64(prime1) + uint64(prime2)) & primeMask) // 606290984
+	prime1minus = uint32((-int64(prime1)) & primeMask)                  // 1640531535
 )
 
 // XXHZero represents an xxhash32 object with seed 0.
@@ -37,10 +38,10 @@
 
 // Reset resets the Hash to its initial state.
 func (xxh *XXHZero) Reset() {
-	xxh.v1 = prime32_1plus2
-	xxh.v2 = prime32_2
+	xxh.v1 = prime1plus2
+	xxh.v2 = prime2
 	xxh.v3 = 0
-	xxh.v4 = prime32_minus1
+	xxh.v4 = prime1minus
 	xxh.totalLen = 0
 	xxh.bufused = 0
 }
@@ -83,20 +84,20 @@
 
 		// fast rotl(13)
 		buf := xxh.buf[:16] // BCE hint.
-		v1 = rol13(v1+binary.LittleEndian.Uint32(buf[:])*prime32_2) * prime32_1
-		v2 = rol13(v2+binary.LittleEndian.Uint32(buf[4:])*prime32_2) * prime32_1
-		v3 = rol13(v3+binary.LittleEndian.Uint32(buf[8:])*prime32_2) * prime32_1
-		v4 = rol13(v4+binary.LittleEndian.Uint32(buf[12:])*prime32_2) * prime32_1
+		v1 = rol13(v1+binary.LittleEndian.Uint32(buf[:])*prime2) * prime1
+		v2 = rol13(v2+binary.LittleEndian.Uint32(buf[4:])*prime2) * prime1
+		v3 = rol13(v3+binary.LittleEndian.Uint32(buf[8:])*prime2) * prime1
+		v4 = rol13(v4+binary.LittleEndian.Uint32(buf[12:])*prime2) * prime1
 		p = r
 		xxh.bufused = 0
 	}
 
 	for n := n - 16; p <= n; p += 16 {
 		sub := input[p:][:16] //BCE hint for compiler
-		v1 = rol13(v1+binary.LittleEndian.Uint32(sub[:])*prime32_2) * prime32_1
-		v2 = rol13(v2+binary.LittleEndian.Uint32(sub[4:])*prime32_2) * prime32_1
-		v3 = rol13(v3+binary.LittleEndian.Uint32(sub[8:])*prime32_2) * prime32_1
-		v4 = rol13(v4+binary.LittleEndian.Uint32(sub[12:])*prime32_2) * prime32_1
+		v1 = rol13(v1+binary.LittleEndian.Uint32(sub[:])*prime2) * prime1
+		v2 = rol13(v2+binary.LittleEndian.Uint32(sub[4:])*prime2) * prime1
+		v3 = rol13(v3+binary.LittleEndian.Uint32(sub[8:])*prime2) * prime1
+		v4 = rol13(v4+binary.LittleEndian.Uint32(sub[12:])*prime2) * prime1
 	}
 	xxh.v1, xxh.v2, xxh.v3, xxh.v4 = v1, v2, v3, v4
 
@@ -112,25 +113,25 @@
 	if h32 >= 16 {
 		h32 += rol1(xxh.v1) + rol7(xxh.v2) + rol12(xxh.v3) + rol18(xxh.v4)
 	} else {
-		h32 += prime32_5
+		h32 += prime5
 	}
 
 	p := 0
 	n := xxh.bufused
 	buf := xxh.buf
 	for n := n - 4; p <= n; p += 4 {
-		h32 += binary.LittleEndian.Uint32(buf[p:p+4]) * prime32_3
-		h32 = rol17(h32) * prime32_4
+		h32 += binary.LittleEndian.Uint32(buf[p:p+4]) * prime3
+		h32 = rol17(h32) * prime4
 	}
 	for ; p < n; p++ {
-		h32 += uint32(buf[p]) * prime32_5
-		h32 = rol11(h32) * prime32_1
+		h32 += uint32(buf[p]) * prime5
+		h32 = rol11(h32) * prime1
 	}
 
 	h32 ^= h32 >> 15
-	h32 *= prime32_2
+	h32 *= prime2
 	h32 ^= h32 >> 13
-	h32 *= prime32_3
+	h32 *= prime3
 	h32 ^= h32 >> 16
 
 	return h32
@@ -142,19 +143,19 @@
 	h32 := uint32(n)
 
 	if n < 16 {
-		h32 += prime32_5
+		h32 += prime5
 	} else {
-		v1 := prime32_1plus2
-		v2 := prime32_2
+		v1 := prime1plus2
+		v2 := prime2
 		v3 := uint32(0)
-		v4 := prime32_minus1
+		v4 := prime1minus
 		p := 0
 		for n := n - 16; p <= n; p += 16 {
 			sub := input[p:][:16] //BCE hint for compiler
-			v1 = rol13(v1+binary.LittleEndian.Uint32(sub[:])*prime32_2) * prime32_1
-			v2 = rol13(v2+binary.LittleEndian.Uint32(sub[4:])*prime32_2) * prime32_1
-			v3 = rol13(v3+binary.LittleEndian.Uint32(sub[8:])*prime32_2) * prime32_1
-			v4 = rol13(v4+binary.LittleEndian.Uint32(sub[12:])*prime32_2) * prime32_1
+			v1 = rol13(v1+binary.LittleEndian.Uint32(sub[:])*prime2) * prime1
+			v2 = rol13(v2+binary.LittleEndian.Uint32(sub[4:])*prime2) * prime1
+			v3 = rol13(v3+binary.LittleEndian.Uint32(sub[8:])*prime2) * prime1
+			v4 = rol13(v4+binary.LittleEndian.Uint32(sub[12:])*prime2) * prime1
 		}
 		input = input[p:]
 		n -= p
@@ -163,19 +164,19 @@
 
 	p := 0
 	for n := n - 4; p <= n; p += 4 {
-		h32 += binary.LittleEndian.Uint32(input[p:p+4]) * prime32_3
-		h32 = rol17(h32) * prime32_4
+		h32 += binary.LittleEndian.Uint32(input[p:p+4]) * prime3
+		h32 = rol17(h32) * prime4
 	}
 	for p < n {
-		h32 += uint32(input[p]) * prime32_5
-		h32 = rol11(h32) * prime32_1
+		h32 += uint32(input[p]) * prime5
+		h32 = rol11(h32) * prime1
 		p++
 	}
 
 	h32 ^= h32 >> 15
-	h32 *= prime32_2
+	h32 *= prime2
 	h32 ^= h32 >> 13
-	h32 *= prime32_3
+	h32 *= prime3
 	h32 ^= h32 >> 16
 
 	return h32
@@ -183,12 +184,12 @@
 
 // Uint32Zero hashes x with seed 0.
 func Uint32Zero(x uint32) uint32 {
-	h := prime32_5 + 4 + x*prime32_3
-	h = rol17(h) * prime32_4
+	h := prime5 + 4 + x*prime3
+	h = rol17(h) * prime4
 	h ^= h >> 15
-	h *= prime32_2
+	h *= prime2
 	h ^= h >> 13
-	h *= prime32_3
+	h *= prime3
 	h ^= h >> 16
 	return h
 }
diff --git a/vendor/github.com/pierrec/lz4/lz4.go b/vendor/github.com/pierrec/lz4/lz4.go
index 3580275..a3284bd 100644
--- a/vendor/github.com/pierrec/lz4/lz4.go
+++ b/vendor/github.com/pierrec/lz4/lz4.go
@@ -10,14 +10,20 @@
 //
 package lz4
 
+import (
+	"math/bits"
+	"sync"
+)
+
 const (
 	// Extension is the LZ4 frame file name extension
 	Extension = ".lz4"
 	// Version is the LZ4 frame format version
 	Version = 1
 
-	frameMagic     uint32 = 0x184D2204
-	frameSkipMagic uint32 = 0x184D2A50
+	frameMagic       uint32 = 0x184D2204
+	frameSkipMagic   uint32 = 0x184D2A50
+	frameMagicLegacy uint32 = 0x184C2102
 
 	// The following constants are used to setup the compression algorithm.
 	minMatch            = 4  // the minimum size of the match sequence size (4 bytes)
@@ -30,26 +36,63 @@
 	// hashLog determines the size of the hash table used to quickly find a previous match position.
 	// Its value influences the compression speed and memory usage, the lower the faster,
 	// but at the expense of the compression ratio.
-	// 16 seems to be the best compromise.
-	hashLog       = 16
-	hashTableSize = 1 << hashLog
-	hashShift     = uint((minMatch * 8) - hashLog)
+	// 16 seems to be the best compromise for fast compression.
+	hashLog = 16
+	htSize  = 1 << hashLog
 
-	mfLimit      = 8 + minMatch // The last match cannot start within the last 12 bytes.
-	skipStrength = 6            // variable step for fast scan
+	mfLimit = 10 + minMatch // The last match cannot start within the last 14 bytes.
 )
 
 // map the block max size id with its value in bytes: 64Kb, 256Kb, 1Mb and 4Mb.
-var (
-	bsMapID    = map[byte]int{4: 64 << 10, 5: 256 << 10, 6: 1 << 20, 7: 4 << 20}
-	bsMapValue = make(map[int]byte, len(bsMapID))
+const (
+	blockSize64K = 1 << (16 + 2*iota)
+	blockSize256K
+	blockSize1M
+	blockSize4M
 )
 
-// Reversed.
-func init() {
-	for i, v := range bsMapID {
-		bsMapValue[v] = i
+var (
+	// Keep a pool of buffers for each valid block sizes.
+	bsMapValue = [...]*sync.Pool{
+		newBufferPool(2 * blockSize64K),
+		newBufferPool(2 * blockSize256K),
+		newBufferPool(2 * blockSize1M),
+		newBufferPool(2 * blockSize4M),
 	}
+)
+
+// newBufferPool returns a pool for buffers of the given size.
+func newBufferPool(size int) *sync.Pool {
+	return &sync.Pool{
+		New: func() interface{} {
+			return make([]byte, size)
+		},
+	}
+}
+
+// getBuffer returns a buffer to its pool.
+func getBuffer(size int) []byte {
+	idx := blockSizeValueToIndex(size) - 4
+	return bsMapValue[idx].Get().([]byte)
+}
+
+// putBuffer returns a buffer to its pool.
+func putBuffer(size int, buf []byte) {
+	if cap(buf) > 0 {
+		idx := blockSizeValueToIndex(size) - 4
+		bsMapValue[idx].Put(buf[:cap(buf)])
+	}
+}
+func blockSizeIndexToValue(i byte) int {
+	return 1 << (16 + 2*uint(i))
+}
+func isValidBlockSize(size int) bool {
+	const blockSizeMask = blockSize64K | blockSize256K | blockSize1M | blockSize4M
+
+	return size&blockSizeMask > 0 && bits.OnesCount(uint(size)) == 1
+}
+func blockSizeValueToIndex(size int) byte {
+	return 4 + byte(bits.TrailingZeros(uint(size)>>16)/2)
 }
 
 // Header describes the various flags that can be set on a Writer or obtained from a Reader.
@@ -57,7 +100,7 @@
 // (http://fastcompression.blogspot.com/2013/04/lz4-streaming-format-final.html).
 //
 // NB. in a Reader, in case of concatenated frames, the Header values may change between Read() calls.
-// It is the caller responsibility to check them if necessary.
+// It is the caller's responsibility to check them if necessary.
 type Header struct {
 	BlockChecksum    bool   // Compressed blocks checksum flag.
 	NoChecksum       bool   // Frame checksum flag.
@@ -66,3 +109,8 @@
 	CompressionLevel int    // Compression level (higher is better, use 0 for fastest compression).
 	done             bool   // Header processed flag (Read or Write and checked).
 }
+
+// Reset reset internal status
+func (h *Header) Reset() {
+	h.done = false
+}
diff --git a/vendor/github.com/pierrec/lz4/reader.go b/vendor/github.com/pierrec/lz4/reader.go
index 81efdbf..87dd72b 100644
--- a/vendor/github.com/pierrec/lz4/reader.go
+++ b/vendor/github.com/pierrec/lz4/reader.go
@@ -14,6 +14,9 @@
 // The Header may change between Read() calls in case of concatenated frames.
 type Reader struct {
 	Header
+	// Handler called when a block has been successfully read.
+	// It provides the number of bytes read.
+	OnBlockDone func(size int)
 
 	buf      [8]byte       // Scrap buffer.
 	pos      int64         // Current position in src.
@@ -22,6 +25,8 @@
 	data     []byte        // Uncompressed data.
 	idx      int           // Index of unread bytes into data.
 	checksum xxh32.XXHZero // Frame hash.
+	skip     int64         // Bytes to skip before next read.
+	dpos     int64         // Position in dest
 }
 
 // NewReader returns a new LZ4 frame decoder.
@@ -76,17 +81,17 @@
 		return fmt.Errorf("lz4: invalid version: got %d; expected %d", v, Version)
 	}
 	if b>>5&1 == 0 {
-		return fmt.Errorf("lz4: block dependency not supported")
+		return ErrBlockDependency
 	}
 	z.BlockChecksum = b>>4&1 > 0
 	frameSize := b>>3&1 > 0
 	z.NoChecksum = b>>2&1 == 0
 
 	bmsID := buf[1] >> 4 & 0x7
-	bSize, ok := bsMapID[bmsID]
-	if !ok {
+	if bmsID < 4 || bmsID > 7 {
 		return fmt.Errorf("lz4: invalid block max size ID: %d", bmsID)
 	}
+	bSize := blockSizeIndexToValue(bmsID - 4)
 	z.BlockMaxSize = bSize
 
 	// Allocate the compressed/uncompressed buffers.
@@ -101,7 +106,7 @@
 	z.data = z.zdata[:cap(z.zdata)][bSize:]
 	z.idx = len(z.data)
 
-	z.checksum.Write(buf[0:2])
+	_, _ = z.checksum.Write(buf[0:2])
 
 	if frameSize {
 		buf := buf[:8]
@@ -110,7 +115,7 @@
 		}
 		z.Size = binary.LittleEndian.Uint64(buf)
 		z.pos += 8
-		z.checksum.Write(buf)
+		_, _ = z.checksum.Write(buf)
 	}
 
 	// Header checksum.
@@ -211,6 +216,9 @@
 				return 0, err
 			}
 			z.pos += int64(bLen)
+			if z.OnBlockDone != nil {
+				z.OnBlockDone(int(bLen))
+			}
 
 			if z.BlockChecksum {
 				checksum, err := z.readUint32()
@@ -255,10 +263,13 @@
 				return 0, err
 			}
 			z.data = z.data[:n]
+			if z.OnBlockDone != nil {
+				z.OnBlockDone(n)
+			}
 		}
 
 		if !z.NoChecksum {
-			z.checksum.Write(z.data)
+			_, _ = z.checksum.Write(z.data)
 			if debugFlag {
 				debug("current frame checksum %x", z.checksum.Sum32())
 			}
@@ -266,8 +277,20 @@
 		z.idx = 0
 	}
 
+	if z.skip > int64(len(z.data[z.idx:])) {
+		z.skip -= int64(len(z.data[z.idx:]))
+		z.dpos += int64(len(z.data[z.idx:]))
+		z.idx = len(z.data)
+		return 0, nil
+	}
+
+	z.idx += int(z.skip)
+	z.dpos += z.skip
+	z.skip = 0
+
 	n := copy(buf, z.data[z.idx:])
 	z.idx += n
+	z.dpos += int64(n)
 	if debugFlag {
 		debug("copied %d bytes to input", n)
 	}
@@ -275,6 +298,20 @@
 	return n, nil
 }
 
+// Seek implements io.Seeker, but supports seeking forward from the current
+// position only. Any other seek will return an error. Allows skipping output
+// bytes which aren't needed, which in some scenarios is faster than reading
+// and discarding them.
+// Note this may cause future calls to Read() to read 0 bytes if all of the
+// data they would have returned is skipped.
+func (z *Reader) Seek(offset int64, whence int) (int64, error) {
+	if offset < 0 || whence != io.SeekCurrent {
+		return z.dpos + z.skip, ErrUnsupportedSeek
+	}
+	z.skip += offset
+	return z.dpos + z.skip, nil
+}
+
 // Reset discards the Reader's state and makes it equivalent to the
 // result of its original state from NewReader, but reading from r instead.
 // This permits reusing a Reader rather than allocating a new one.
diff --git a/vendor/github.com/pierrec/lz4/reader_legacy.go b/vendor/github.com/pierrec/lz4/reader_legacy.go
new file mode 100644
index 0000000..1670a77
--- /dev/null
+++ b/vendor/github.com/pierrec/lz4/reader_legacy.go
@@ -0,0 +1,207 @@
+package lz4
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+)
+
+// ReaderLegacy implements the LZ4Demo frame decoder.
+// The Header is set after the first call to Read().
+type ReaderLegacy struct {
+	Header
+	// Handler called when a block has been successfully read.
+	// It provides the number of bytes read.
+	OnBlockDone func(size int)
+
+	lastBlock bool
+	buf       [8]byte   // Scrap buffer.
+	pos       int64     // Current position in src.
+	src       io.Reader // Source.
+	zdata     []byte    // Compressed data.
+	data      []byte    // Uncompressed data.
+	idx       int       // Index of unread bytes into data.
+	skip      int64     // Bytes to skip before next read.
+	dpos      int64     // Position in dest
+}
+
+// NewReaderLegacy returns a new LZ4Demo frame decoder.
+// No access to the underlying io.Reader is performed.
+func NewReaderLegacy(src io.Reader) *ReaderLegacy {
+	r := &ReaderLegacy{src: src}
+	return r
+}
+
+// readHeader checks the frame magic number and parses the frame descriptoz.
+// Skippable frames are supported even as a first frame although the LZ4
+// specifications recommends skippable frames not to be used as first frames.
+func (z *ReaderLegacy) readLegacyHeader() error {
+	z.lastBlock = false
+	magic, err := z.readUint32()
+	if err != nil {
+		z.pos += 4
+		if err == io.ErrUnexpectedEOF {
+			return io.EOF
+		}
+		return err
+	}
+	if magic != frameMagicLegacy {
+		return ErrInvalid
+	}
+	z.pos += 4
+
+	// Legacy has fixed 8MB blocksizes
+	// https://github.com/lz4/lz4/blob/dev/doc/lz4_Frame_format.md#legacy-frame
+	bSize := blockSize4M * 2
+
+	// Allocate the compressed/uncompressed buffers.
+	// The compressed buffer cannot exceed the uncompressed one.
+	if n := 2 * bSize; cap(z.zdata) < n {
+		z.zdata = make([]byte, n, n)
+	}
+	if debugFlag {
+		debug("header block max size size=%d", bSize)
+	}
+	z.zdata = z.zdata[:bSize]
+	z.data = z.zdata[:cap(z.zdata)][bSize:]
+	z.idx = len(z.data)
+
+	z.Header.done = true
+	if debugFlag {
+		debug("header read: %v", z.Header)
+	}
+
+	return nil
+}
+
+// Read decompresses data from the underlying source into the supplied buffer.
+//
+// Since there can be multiple streams concatenated, Header values may
+// change between calls to Read(). If that is the case, no data is actually read from
+// the underlying io.Reader, to allow for potential input buffer resizing.
+func (z *ReaderLegacy) Read(buf []byte) (int, error) {
+	if debugFlag {
+		debug("Read buf len=%d", len(buf))
+	}
+	if !z.Header.done {
+		if err := z.readLegacyHeader(); err != nil {
+			return 0, err
+		}
+		if debugFlag {
+			debug("header read OK compressed buffer %d / %d uncompressed buffer %d : %d index=%d",
+				len(z.zdata), cap(z.zdata), len(z.data), cap(z.data), z.idx)
+		}
+	}
+
+	if len(buf) == 0 {
+		return 0, nil
+	}
+
+	if z.idx == len(z.data) {
+		// No data ready for reading, process the next block.
+		if debugFlag {
+			debug("  reading block from writer %d %d", z.idx, blockSize4M*2)
+		}
+
+		// Reset uncompressed buffer
+		z.data = z.zdata[:cap(z.zdata)][len(z.zdata):]
+
+		bLen, err := z.readUint32()
+		if err != nil {
+			return 0, err
+		}
+		if debugFlag {
+			debug("   bLen %d (0x%x) offset = %d (0x%x)", bLen, bLen, z.pos, z.pos)
+		}
+		z.pos += 4
+
+		// Legacy blocks are always compressed, even when detrimental
+		if debugFlag {
+			debug("   compressed block size %d", bLen)
+		}
+
+		if int(bLen) > cap(z.data) {
+			return 0, fmt.Errorf("lz4: invalid block size: %d", bLen)
+		}
+		zdata := z.zdata[:bLen]
+		if _, err := io.ReadFull(z.src, zdata); err != nil {
+			return 0, err
+		}
+		z.pos += int64(bLen)
+
+		n, err := UncompressBlock(zdata, z.data)
+		if err != nil {
+			return 0, err
+		}
+
+		z.data = z.data[:n]
+		if z.OnBlockDone != nil {
+			z.OnBlockDone(n)
+		}
+
+		z.idx = 0
+
+		// Legacy blocks are fixed to 8MB, if we read a decompressed block smaller than this
+		// it means we've reached the end...
+		if n < blockSize4M*2 {
+			z.lastBlock = true
+		}
+	}
+
+	if z.skip > int64(len(z.data[z.idx:])) {
+		z.skip -= int64(len(z.data[z.idx:]))
+		z.dpos += int64(len(z.data[z.idx:]))
+		z.idx = len(z.data)
+		return 0, nil
+	}
+
+	z.idx += int(z.skip)
+	z.dpos += z.skip
+	z.skip = 0
+
+	n := copy(buf, z.data[z.idx:])
+	z.idx += n
+	z.dpos += int64(n)
+	if debugFlag {
+		debug("%v] copied %d bytes to input (%d:%d)", z.lastBlock, n, z.idx, len(z.data))
+	}
+	if z.lastBlock && len(z.data) == z.idx {
+		return n, io.EOF
+	}
+	return n, nil
+}
+
+// Seek implements io.Seeker, but supports seeking forward from the current
+// position only. Any other seek will return an error. Allows skipping output
+// bytes which aren't needed, which in some scenarios is faster than reading
+// and discarding them.
+// Note this may cause future calls to Read() to read 0 bytes if all of the
+// data they would have returned is skipped.
+func (z *ReaderLegacy) Seek(offset int64, whence int) (int64, error) {
+	if offset < 0 || whence != io.SeekCurrent {
+		return z.dpos + z.skip, ErrUnsupportedSeek
+	}
+	z.skip += offset
+	return z.dpos + z.skip, nil
+}
+
+// Reset discards the Reader's state and makes it equivalent to the
+// result of its original state from NewReader, but reading from r instead.
+// This permits reusing a Reader rather than allocating a new one.
+func (z *ReaderLegacy) Reset(r io.Reader) {
+	z.Header = Header{}
+	z.pos = 0
+	z.src = r
+	z.zdata = z.zdata[:0]
+	z.data = z.data[:0]
+	z.idx = 0
+}
+
+// readUint32 reads an uint32 into the supplied buffer.
+// The idea is to make use of the already allocated buffers avoiding additional allocations.
+func (z *ReaderLegacy) readUint32() (uint32, error) {
+	buf := z.buf[:4]
+	_, err := io.ReadFull(z.src, buf)
+	x := binary.LittleEndian.Uint32(buf)
+	return x, err
+}
diff --git a/vendor/github.com/pierrec/lz4/writer.go b/vendor/github.com/pierrec/lz4/writer.go
index 0120438..f066d56 100644
--- a/vendor/github.com/pierrec/lz4/writer.go
+++ b/vendor/github.com/pierrec/lz4/writer.go
@@ -4,21 +4,35 @@
 	"encoding/binary"
 	"fmt"
 	"io"
+	"runtime"
 
 	"github.com/pierrec/lz4/internal/xxh32"
 )
 
+// zResult contains the results of compressing a block.
+type zResult struct {
+	size     uint32 // Block header
+	data     []byte // Compressed data
+	checksum uint32 // Data checksum
+}
+
 // Writer implements the LZ4 frame encoder.
 type Writer struct {
 	Header
+	// Handler called when a block has been successfully written out.
+	// It provides the number of bytes written.
+	OnBlockDone func(size int)
 
 	buf       [19]byte      // magic number(4) + header(flags(2)+[Size(8)+DictID(4)]+checksum(1)) does not exceed 19 bytes
 	dst       io.Writer     // Destination.
 	checksum  xxh32.XXHZero // Frame checksum.
-	zdata     []byte        // Compressed data.
-	data      []byte        // Data to be compressed.
+	data      []byte        // Data to be compressed + buffer for compressed data.
 	idx       int           // Index into data.
 	hashtable [winSize]int  // Hash table used in CompressBlock().
+
+	// For concurrency.
+	c   chan chan zResult // Channel for block compression goroutines and writer goroutine.
+	err error             // Any error encountered while writing to the underlying destination.
 }
 
 // NewWriter returns a new LZ4 frame encoder.
@@ -26,28 +40,90 @@
 // The supplied Header is checked at the first Write.
 // It is ok to change it before the first Write but then not until a Reset() is performed.
 func NewWriter(dst io.Writer) *Writer {
-	return &Writer{dst: dst}
+	z := new(Writer)
+	z.Reset(dst)
+	return z
+}
+
+// WithConcurrency sets the number of concurrent go routines used for compression.
+// A negative value sets the concurrency to GOMAXPROCS.
+func (z *Writer) WithConcurrency(n int) *Writer {
+	switch {
+	case n == 0 || n == 1:
+		z.c = nil
+		return z
+	case n < 0:
+		n = runtime.GOMAXPROCS(0)
+	}
+	z.c = make(chan chan zResult, n)
+	// Writer goroutine managing concurrent block compression goroutines.
+	go func() {
+		// Process next block compression item.
+		for c := range z.c {
+			// Read the next compressed block result.
+			// Waiting here ensures that the blocks are output in the order they were sent.
+			// The incoming channel is always closed as it indicates to the caller that
+			// the block has been processed.
+			res := <-c
+			n := len(res.data)
+			if n == 0 {
+				// Notify the block compression routine that we are done with its result.
+				// This is used when a sentinel block is sent to terminate the compression.
+				close(c)
+				return
+			}
+			// Write the block.
+			if err := z.writeUint32(res.size); err != nil && z.err == nil {
+				z.err = err
+			}
+			if _, err := z.dst.Write(res.data); err != nil && z.err == nil {
+				z.err = err
+			}
+			if z.BlockChecksum {
+				if err := z.writeUint32(res.checksum); err != nil && z.err == nil {
+					z.err = err
+				}
+			}
+			// It is now safe to release the buffer as no longer in use by any goroutine.
+			putBuffer(cap(res.data), res.data)
+			if h := z.OnBlockDone; h != nil {
+				h(n)
+			}
+			close(c)
+		}
+	}()
+	return z
+}
+
+// newBuffers instantiates new buffers which size matches the one in Header.
+// The returned buffers are for decompression and compression respectively.
+func (z *Writer) newBuffers() {
+	bSize := z.Header.BlockMaxSize
+	buf := getBuffer(bSize)
+	z.data = buf[:bSize] // Uncompressed buffer is the first half.
+}
+
+// freeBuffers puts the writer's buffers back to the pool.
+func (z *Writer) freeBuffers() {
+	// Put the buffer back into the pool, if any.
+	putBuffer(z.Header.BlockMaxSize, z.data)
+	z.data = nil
 }
 
 // writeHeader builds and writes the header (magic+header) to the underlying io.Writer.
 func (z *Writer) writeHeader() error {
 	// Default to 4Mb if BlockMaxSize is not set.
 	if z.Header.BlockMaxSize == 0 {
-		z.Header.BlockMaxSize = bsMapID[7]
+		z.Header.BlockMaxSize = blockSize4M
 	}
 	// The only option that needs to be validated.
 	bSize := z.Header.BlockMaxSize
-	bSizeID, ok := bsMapValue[bSize]
-	if !ok {
+	if !isValidBlockSize(z.Header.BlockMaxSize) {
 		return fmt.Errorf("lz4: invalid block max size: %d", bSize)
 	}
 	// Allocate the compressed/uncompressed buffers.
 	// The compressed buffer cannot exceed the uncompressed one.
-	if n := 2 * bSize; cap(z.zdata) < n {
-		z.zdata = make([]byte, n, n)
-	}
-	z.zdata = z.zdata[:bSize]
-	z.data = z.zdata[:cap(z.zdata)][bSize:]
+	z.newBuffers()
 	z.idx = 0
 
 	// Size is optional.
@@ -67,7 +143,7 @@
 		flg |= 1 << 2
 	}
 	buf[4] = flg
-	buf[5] = bSizeID << 4
+	buf[5] = blockSizeValueToIndex(z.Header.BlockMaxSize) << 4
 
 	// Current buffer size: magic(4) + flags(1) + block max size (1).
 	n := 6
@@ -147,28 +223,39 @@
 // compressBlock compresses a block.
 func (z *Writer) compressBlock(data []byte) error {
 	if !z.NoChecksum {
-		z.checksum.Write(data)
+		_, _ = z.checksum.Write(data)
 	}
 
+	if z.c != nil {
+		c := make(chan zResult)
+		z.c <- c // Send now to guarantee order
+
+		// get a buffer from the pool and copy the data over
+		block := getBuffer(z.Header.BlockMaxSize)[:len(data)]
+		copy(block, data)
+
+		go writerCompressBlock(c, z.Header, block)
+		return nil
+	}
+
+	zdata := z.data[z.Header.BlockMaxSize:cap(z.data)]
 	// The compressed block size cannot exceed the input's.
 	var zn int
-	var err error
 
 	if level := z.Header.CompressionLevel; level != 0 {
-		zn, err = CompressBlockHC(data, z.zdata, level)
+		zn, _ = CompressBlockHC(data, zdata, level)
 	} else {
-		zn, err = CompressBlock(data, z.zdata, z.hashtable[:])
+		zn, _ = CompressBlock(data, zdata, z.hashtable[:])
 	}
 
-	var zdata []byte
 	var bLen uint32
 	if debugFlag {
 		debug("block compression %d => %d", len(data), zn)
 	}
-	if err == nil && zn > 0 && zn < len(data) {
+	if zn > 0 && zn < len(data) {
 		// Compressible and compressed size smaller than uncompressed: ok!
 		bLen = uint32(zn)
-		zdata = z.zdata[:zn]
+		zdata = zdata[:zn]
 	} else {
 		// Uncompressed block.
 		bLen = uint32(len(data)) | compressedBlockFlag
@@ -182,24 +269,26 @@
 	if err := z.writeUint32(bLen); err != nil {
 		return err
 	}
-	if _, err := z.dst.Write(zdata); err != nil {
+	written, err := z.dst.Write(zdata)
+	if err != nil {
 		return err
 	}
+	if h := z.OnBlockDone; h != nil {
+		h(written)
+	}
 
-	if z.BlockChecksum {
-		checksum := xxh32.ChecksumZero(zdata)
+	if !z.BlockChecksum {
 		if debugFlag {
-			debug("block checksum %x", checksum)
+			debug("current frame checksum %x", z.checksum.Sum32())
 		}
-		if err := z.writeUint32(checksum); err != nil {
-			return err
-		}
+		return nil
 	}
+	checksum := xxh32.ChecksumZero(zdata)
 	if debugFlag {
-		debug("current frame checksum %x", z.checksum.Sum32())
+		debug("block checksum %x", checksum)
+		defer func() { debug("current frame checksum %x", z.checksum.Sum32()) }()
 	}
-
-	return nil
+	return z.writeUint32(checksum)
 }
 
 // Flush flushes any pending compressed data to the underlying writer.
@@ -213,7 +302,35 @@
 		return nil
 	}
 
-	return z.compressBlock(z.data[:z.idx])
+	data := getBuffer(z.Header.BlockMaxSize)[:len(z.data[:z.idx])]
+	copy(data, z.data[:z.idx])
+
+	z.idx = 0
+	if z.c == nil {
+		return z.compressBlock(data)
+	}
+	if !z.NoChecksum {
+		_, _ = z.checksum.Write(data)
+	}
+	c := make(chan zResult)
+	z.c <- c
+	writerCompressBlock(c, z.Header, data)
+	return nil
+}
+
+func (z *Writer) close() error {
+	if z.c == nil {
+		return nil
+	}
+	// Send a sentinel block (no data to compress) to terminate the writer main goroutine.
+	c := make(chan zResult)
+	z.c <- c
+	c <- zResult{}
+	// Wait for the main goroutine to complete.
+	<-c
+	// At this point the main goroutine has shut down or is about to return.
+	z.c = nil
+	return z.err
 }
 
 // Close closes the Writer, flushing any unwritten data to the underlying io.Writer, but does not close the underlying io.Writer.
@@ -223,10 +340,13 @@
 			return err
 		}
 	}
-
 	if err := z.Flush(); err != nil {
 		return err
 	}
+	if err := z.close(); err != nil {
+		return err
+	}
+	z.freeBuffers()
 
 	if debugFlag {
 		debug("writing last empty block")
@@ -234,28 +354,33 @@
 	if err := z.writeUint32(0); err != nil {
 		return err
 	}
-	if !z.NoChecksum {
-		checksum := z.checksum.Sum32()
-		if debugFlag {
-			debug("stream checksum %x", checksum)
-		}
-		if err := z.writeUint32(checksum); err != nil {
-			return err
-		}
+	if z.NoChecksum {
+		return nil
 	}
-	return nil
+	checksum := z.checksum.Sum32()
+	if debugFlag {
+		debug("stream checksum %x", checksum)
+	}
+	return z.writeUint32(checksum)
 }
 
 // Reset clears the state of the Writer z such that it is equivalent to its
 // initial state from NewWriter, but instead writing to w.
 // No access to the underlying io.Writer is performed.
 func (z *Writer) Reset(w io.Writer) {
-	z.Header = Header{}
+	n := cap(z.c)
+	_ = z.close()
+	z.freeBuffers()
+	z.Header.Reset()
 	z.dst = w
 	z.checksum.Reset()
-	z.zdata = z.zdata[:0]
-	z.data = z.data[:0]
 	z.idx = 0
+	z.err = nil
+	// reset hashtable to ensure deterministic output.
+	for i := range z.hashtable {
+		z.hashtable[i] = 0
+	}
+	z.WithConcurrency(n)
 }
 
 // writeUint32 writes a uint32 to the underlying writer.
@@ -265,3 +390,33 @@
 	_, err := z.dst.Write(buf)
 	return err
 }
+
+// writerCompressBlock compresses data into a pooled buffer and writes its result
+// out to the input channel.
+func writerCompressBlock(c chan zResult, header Header, data []byte) {
+	zdata := getBuffer(header.BlockMaxSize)
+	// The compressed block size cannot exceed the input's.
+	var zn int
+	if level := header.CompressionLevel; level != 0 {
+		zn, _ = CompressBlockHC(data, zdata, level)
+	} else {
+		var hashTable [winSize]int
+		zn, _ = CompressBlock(data, zdata, hashTable[:])
+	}
+	var res zResult
+	if zn > 0 && zn < len(data) {
+		res.size = uint32(zn)
+		res.data = zdata[:zn]
+		// release the uncompressed block since it is not used anymore
+		putBuffer(header.BlockMaxSize, data)
+	} else {
+		res.size = uint32(len(data)) | compressedBlockFlag
+		res.data = data
+		// release the compressed block since it was not used
+		putBuffer(header.BlockMaxSize, zdata)
+	}
+	if header.BlockChecksum {
+		res.checksum = xxh32.ChecksumZero(res.data)
+	}
+	c <- res
+}
diff --git a/vendor/github.com/pierrec/lz4/writer_legacy.go b/vendor/github.com/pierrec/lz4/writer_legacy.go
new file mode 100644
index 0000000..ca8dc8c
--- /dev/null
+++ b/vendor/github.com/pierrec/lz4/writer_legacy.go
@@ -0,0 +1,182 @@
+package lz4
+
+import (
+	"encoding/binary"
+	"io"
+)
+
+// WriterLegacy implements the LZ4Demo frame decoder.
+type WriterLegacy struct {
+	Header
+	// Handler called when a block has been successfully read.
+	// It provides the number of bytes read.
+	OnBlockDone func(size int)
+
+	dst       io.Writer    // Destination.
+	data      []byte       // Data to be compressed + buffer for compressed data.
+	idx       int          // Index into data.
+	hashtable [winSize]int // Hash table used in CompressBlock().
+}
+
+// NewWriterLegacy returns a new LZ4 encoder for the legacy frame format.
+// No access to the underlying io.Writer is performed.
+// The supplied Header is checked at the first Write.
+// It is ok to change it before the first Write but then not until a Reset() is performed.
+func NewWriterLegacy(dst io.Writer) *WriterLegacy {
+	z := new(WriterLegacy)
+	z.Reset(dst)
+	return z
+}
+
+// Write compresses data from the supplied buffer into the underlying io.Writer.
+// Write does not return until the data has been written.
+func (z *WriterLegacy) Write(buf []byte) (int, error) {
+	if !z.Header.done {
+		if err := z.writeHeader(); err != nil {
+			return 0, err
+		}
+	}
+	if debugFlag {
+		debug("input buffer len=%d index=%d", len(buf), z.idx)
+	}
+
+	zn := len(z.data)
+	var n int
+	for len(buf) > 0 {
+		if z.idx == 0 && len(buf) >= zn {
+			// Avoid a copy as there is enough data for a block.
+			if err := z.compressBlock(buf[:zn]); err != nil {
+				return n, err
+			}
+			n += zn
+			buf = buf[zn:]
+			continue
+		}
+		// Accumulate the data to be compressed.
+		m := copy(z.data[z.idx:], buf)
+		n += m
+		z.idx += m
+		buf = buf[m:]
+		if debugFlag {
+			debug("%d bytes copied to buf, current index %d", n, z.idx)
+		}
+
+		if z.idx < len(z.data) {
+			// Buffer not filled.
+			if debugFlag {
+				debug("need more data for compression")
+			}
+			return n, nil
+		}
+
+		// Buffer full.
+		if err := z.compressBlock(z.data); err != nil {
+			return n, err
+		}
+		z.idx = 0
+	}
+
+	return n, nil
+}
+
+// writeHeader builds and writes the header to the underlying io.Writer.
+func (z *WriterLegacy) writeHeader() error {
+	// Legacy has fixed 8MB blocksizes
+	// https://github.com/lz4/lz4/blob/dev/doc/lz4_Frame_format.md#legacy-frame
+	bSize := 2 * blockSize4M
+
+	buf := make([]byte, 2*bSize, 2*bSize)
+	z.data = buf[:bSize] // Uncompressed buffer is the first half.
+
+	z.idx = 0
+
+	// Header consists of one mageic number, write it out.
+	if err := binary.Write(z.dst, binary.LittleEndian, frameMagicLegacy); err != nil {
+		return err
+	}
+	z.Header.done = true
+	if debugFlag {
+		debug("wrote header %v", z.Header)
+	}
+
+	return nil
+}
+
+// compressBlock compresses a block.
+func (z *WriterLegacy) compressBlock(data []byte) error {
+	bSize := 2 * blockSize4M
+	zdata := z.data[bSize:cap(z.data)]
+	// The compressed block size cannot exceed the input's.
+	var zn int
+
+	if level := z.Header.CompressionLevel; level != 0 {
+		zn, _ = CompressBlockHC(data, zdata, level)
+	} else {
+		zn, _ = CompressBlock(data, zdata, z.hashtable[:])
+	}
+
+	if debugFlag {
+		debug("block compression %d => %d", len(data), zn)
+	}
+	zdata = zdata[:zn]
+
+	// Write the block.
+	if err := binary.Write(z.dst, binary.LittleEndian, uint32(zn)); err != nil {
+		return err
+	}
+	written, err := z.dst.Write(zdata)
+	if err != nil {
+		return err
+	}
+	if h := z.OnBlockDone; h != nil {
+		h(written)
+	}
+	return nil
+}
+
+// Flush flushes any pending compressed data to the underlying writer.
+// Flush does not return until the data has been written.
+// If the underlying writer returns an error, Flush returns that error.
+func (z *WriterLegacy) Flush() error {
+	if debugFlag {
+		debug("flush with index %d", z.idx)
+	}
+	if z.idx == 0 {
+		return nil
+	}
+
+	data := z.data[:z.idx]
+	z.idx = 0
+	return z.compressBlock(data)
+}
+
+// Close closes the WriterLegacy, flushing any unwritten data to the underlying io.Writer, but does not close the underlying io.Writer.
+func (z *WriterLegacy) Close() error {
+	if !z.Header.done {
+		if err := z.writeHeader(); err != nil {
+			return err
+		}
+	}
+	if err := z.Flush(); err != nil {
+		return err
+	}
+
+	if debugFlag {
+		debug("writing last empty block")
+	}
+
+	return nil
+}
+
+// Reset clears the state of the WriterLegacy z such that it is equivalent to its
+// initial state from NewWriterLegacy, but instead writing to w.
+// No access to the underlying io.Writer is performed.
+func (z *WriterLegacy) Reset(w io.Writer) {
+	z.Header.Reset()
+	z.dst = w
+	z.idx = 0
+	// reset hashtable to ensure deterministic output.
+	for i := range z.hashtable {
+		z.hashtable[i] = 0
+	}
+}