internal static void WriteToAsync <T>(this Stream stream, Stream toStream, long?copyLength, long?maxLength, bool calculateMd5, ExecutionState <T> executionState, StreamDescriptor streamCopyState, Action <ExecutionState <T> > completed)
{
AsyncStreamCopier <T> copier = new AsyncStreamCopier <T>(stream, toStream, executionState, GetBufferSize(stream), calculateMd5, streamCopyState);
copier.StartCopyStream(completed, copyLength, maxLength);
}
