static allData(callback) {
    return (box) => {
      const all = box.reader.getLength() - box.reader.getPosition();
      callback(box.reader.readBytes(all));
    };
  }
Create a callback that tells the Mp4 parser to treat the body of a box as a
binary blob and to parse the body's contents using the provided callback.

@param {function(!Uint8Array)} callback
@return {!shaka.util.Mp4Parser.CallbackType}
@export