readInto method
Implementation
@override
Future<ReadResult> readInto(ReadBuf dst) async {
if (_position >= end) return const ReadResult(0, eof: true);
final n = (end - _position).clamp(0, dst.remaining);
dst.unfilled.setRange(0, n, bytes, _position);
dst.advance(n);
_position += n;
return ReadResult(n, eof: _position >= end);
}