code: function (message, payloadType, encoding) {
      return module.exports.decode(message.payload, payloadType, encoding)
    }
docs: Convert the payload in the supplied DXL message to the supplied
  payloadType. If the payloadType is 'bin', the payload is returned as a
  binary buffer. If the payloadType is 'obj', the payload is returned as an
  object, deserialized from a JSON string. If the payloadType is 'txt' (or
  anything else), the payload is returned as a string.
  @param {external:Message} message - The DXL message.
  @param {String} payloadType - One of 'bin', 'obj', or 'txt'.
  @param {String} [encoding=utf8] - The encoding of the payload. (Unused
  when payloadType is 'bin'.)
  @returns {(Buffer|Object|String)} The value converted from the buffer.
  @throws {TypeError} If 'bin' is requested but the payload in the message is
  not a binary buffer.