readAtSync method
Reads exactly length bytes starting at offset.
Implementation
@override
Uint8List readAtSync(int offset, int length) {
_checkOpen();
if (offset < 0 || length < 0 || offset + length > _length) {
throw RangeError(
'read [$offset, ${offset + length}) outside 0..$_length',
);
}
return Uint8List.sublistView(_data, offset, offset + length);
}