code: private static int computeChecksum(byte[] buf, int offset, int length, String channel) {
          Hasher hasher = Hashing.murmur3_32().newHasher();
          hasher.putBytes(buf, offset, length);
          hasher.putUnencodedChars(channel);
          return hasher.hash().asInt() & 0xffff;
      }
docs: Computes a 16-bit checksum of the contents of the specific ByteBuffer and channel name.