writeFrom method
override
    Writes from a buffer to the file.
Will read the buffer from index start to index end.
The start must be non-negative and no greater than buffer.length.
If end is omitted, it defaults to buffer.length.
Otherwise end must be no less than start
and no greater than buffer.length.
Returns a Future<RandomAccessFile> that completes with this
RandomAccessFile when the write completes.
Implementation
@override
Future<io.RandomAccessFile> writeFrom(
  List<int> buffer, [
  int start = 0,
  int? end,
]) async {
  await delegate.writeFrom(buffer, start, end);
  return this;
}