code: function swap(bytes, offset, index) {
    offset--;
    for(let x = 0; x < offset; x++) {
      /** @type {*} */
      let theByte = bytes[index + x];
      bytes[index + x] = bytes[index + offset];
      bytes[index + offset] = theByte;
      offset--;
    }
  }
docs: Swap the byte order of a value in a buffer. The buffer is modified in place.
  @param {!Array|!Uint8Array} bytes The bytes.
  @param {number} offset The byte offset.
  @param {number} index The start index.
  @private