Add msgpack wire protocol with halfsiphash checksums

lib/msgpack/unsafe.go

@@ -0,0 +1,22 @@
+// +build !appengine
+
+package msgpack
+
+import (
+	"unsafe"
+)
+
+// bytesToString converts byte slice to string.
+func bytesToString(b []byte) string {
+	return *(*string)(unsafe.Pointer(&b))
+}
+
+// stringToBytes converts string to byte slice.
+func stringToBytes(s string) []byte {
+	return *(*[]byte)(unsafe.Pointer(
+		&struct {
+			string
+			Cap int
+		}{s, len(s)},
+	))
+}