VOL-2496 Add "event listen" command to voltctl

Change-Id: I8f1fb34b55f56c8125142ac289e2f19fc170d804
diff --git a/vendor/github.com/pierrec/lz4/lz4.go b/vendor/github.com/pierrec/lz4/lz4.go
new file mode 100644
index 0000000..cdbf961
--- /dev/null
+++ b/vendor/github.com/pierrec/lz4/lz4.go
@@ -0,0 +1,66 @@
+// 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.
+//
+// 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.
+// For a complete description of an lz4 compressed block, see:
+// http://fastcompression.blogspot.fr/2011/05/lz4-explained.html
+//
+// See https://github.com/Cyan4973/lz4 for the reference C implementation.
+//
+package lz4
+
+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
+
+	// The following constants are used to setup the compression algorithm.
+	minMatch            = 4  // the minimum size of the match sequence size (4 bytes)
+	winSizeLog          = 16 // LZ4 64Kb window size limit
+	winSize             = 1 << winSizeLog
+	winMask             = winSize - 1 // 64Kb window of previous data for dependent blocks
+	compressedBlockFlag = 1 << 31
+	compressedBlockMask = compressedBlockFlag - 1
+
+	// 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 for fast compression.
+	hashLog = 16
+	htSize  = 1 << hashLog
+
+	mfLimit = 8 + minMatch // The last match cannot start within the last 12 bytes.
+)
+
+// map the block max size id with its value in bytes: 64Kb, 256Kb, 1Mb and 4Mb.
+const (
+	blockSize64K  = 64 << 10
+	blockSize256K = 256 << 10
+	blockSize1M   = 1 << 20
+	blockSize4M   = 4 << 20
+)
+
+var (
+	bsMapID    = map[byte]int{4: blockSize64K, 5: blockSize256K, 6: blockSize1M, 7: blockSize4M}
+	bsMapValue = map[int]byte{blockSize64K: 4, blockSize256K: 5, blockSize1M: 6, blockSize4M: 7}
+)
+
+// Header describes the various flags that can be set on a Writer or obtained from a Reader.
+// The default values match those of the LZ4 frame format definition
+// (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.
+type Header struct {
+	BlockChecksum    bool   // Compressed blocks checksum flag.
+	NoChecksum       bool   // Frame checksum flag.
+	BlockMaxSize     int    // Size of the uncompressed data block (one of [64KB, 256KB, 1MB, 4MB]). Default=4MB.
+	Size             uint64 // Frame total size. It is _not_ computed by the Writer.
+	CompressionLevel int    // Compression level (higher is better, use 0 for fastest compression).
+	done             bool   // Header processed flag (Read or Write and checked).
+}