flush method
      
void
flush()
      
     
    
    
Implementation
void flush() {
  if (_pieces.isNotEmpty) {
    var buf = Uint8List.fromList(_pieces);
    _parts.add(buf.buffer);
    _pieces = [];
  }
}void flush() {
  if (_pieces.isNotEmpty) {
    var buf = Uint8List.fromList(_pieces);
    _parts.add(buf.buffer);
    _pieces = [];
  }
}