code: function FilteraddMessage(arg, options) {
    Message.call(this, options);
    this.command = 'filteradd';
    $.checkArgument(
      _.isUndefined(arg) || BufferUtil.isBuffer(arg),
      'First argument is expected to be a Buffer or undefined'
    );
    this.data = arg || BufferUtil.EMPTY_BUFFER;
  }
docs: Request peer to add data to a bloom filter already set by 'filterload'
  @param {Buffer=} data - Array of bytes representing bloom filter data
  @param {Object=} options
  @extends Message
  @constructor