///<summary>
///Writes asynchronously a sequence of bytes to the current stream and advances the current position within this stream by the number of bytes written.
///</summary>
///<returns>A Task that represents the asynchronous write.</returns>
///<param name="source">The source.</param>
///<param name="buffer">The buffer containing data to write to the current stream.</param>
///<param name="offset">The zero-based byte offset in at which to begin copying bytes to the current stream.</param>
///<param name="count">The maximum number of bytes to write. </param>
/// <param name="cancellationToken">The cancellation token.</param>
///<exception cref="T:System.ArgumentException"> length minus <paramref name="offset" /> is less than <paramref name="count" />. </exception>
///<exception cref="T:System.ArgumentNullException"> is null. </exception>
///<exception cref="T:System.ArgumentOutOfRangeException"> or <paramref name="count" /> is negative. </exception>
///<exception cref="T:System.NotSupportedException">The stream does not support writing. </exception>
///<exception cref="T:System.ObjectDisposedException">The stream is closed. </exception>
///<exception cref="T:System.IO.IOException">An I/O error occurred. </exception>
public static Task WriteAsync(this System.IO.Stream source, byte[] buffer, int offset, int count, System.Threading.CancellationToken cancellationToken)
{
if (cancellationToken.IsCancellationRequested)
{
return(TaskServices.FromCancellation(cancellationToken));
}
return(Task.Factory.FromAsync(source.BeginWrite, source.EndWrite, buffer, offset, count, null));
}
///<summary>
///Flushes asynchronously the current stream.
///</summary>
///<returns>A Task that represents the asynchronous flush.</returns>
public static Task FlushAsync(this System.IO.Stream source, System.Threading.CancellationToken cancellationToken)
{
if (cancellationToken.IsCancellationRequested)
{
return(TaskServices.FromCancellation(cancellationToken));
}
return(Task.Factory.StartNew(s => ((System.IO.Stream)s).Flush(), source, cancellationToken, TaskCreationOptions.None, TaskScheduler.Default));
}