Add msgpack wire protocol with halfsiphash checksums

lib/msgpack/safe.go

@@ -0,0 +1,13 @@
+// +build appengine
+
+package msgpack
+
+// bytesToString converts byte slice to string.
+func bytesToString(b []byte) string {
+	return string(b)
+}
+
+// stringToBytes converts string to byte slice.
+func stringToBytes(s string) []byte {
+	return []byte(s)
+}