code: void writeBytes(byte[] bytes) throws IOException {
          int size = bytes.length;
          if (size < 256) {
              output.writeByte(BIN_8);
              output.writeByte(size);
          } else if (size < 65536) {
              output.writeByte(BIN_16);
              output.writeShort(size);
          } else {
              output.writeByte(BIN_32);
              output.writeInt(size);
          }
          output.write(bytes);
      }
docs: Writes a MessagePack byte block.
  
  @param bytes  the bytes, not null
  @throws IOException if an error occurs