code: function encode(arr, buf) {
    assert(Array.isArray(arr), 'array expected');
    buf = buf || new Buffer(0);
    buf = _arr(buf, arr);
    return buf;
  }
docs: Pack an array.
  
  @param arr An array of values.
  @param buf A buffer to append the encoded contents to (optional).
  
  @return A buffer with the RESP encoded contents.