Reads into an existing List<int> from the file. If start is present, the bytes will be filled into buffer from at index start, otherwise index 0. If end is present, the end - start byte...
Reads into an existing List<int> from the file. If start is present, the bytes will be filled into buffer from at index start, otherwise index 0. If end is present, the end - start bytes will be read into buffer, otherwise up to buffer.length. If end == start nothing happends.
Returns a Future<int>
that completes with the number of bytes read.