Is it possible to use NetworkStream.WriteAsync(ReadOnlyMemory<byte>) under .NET Standard 2.0?

[GF-Huang]

Is there any nuget packages contains something stream extensions to do this?

[huoyaoyuan]

Packages can provide additional types, but can't extend members on existing type.

runtime/src/libraries/System.Private.CoreLib/src/System/IO/Stream.cs

Lines 609 to 619 in 1fe9cbf

	public virtual ValueTask WriteAsync(ReadOnlyMemory<byte> buffer, CancellationToken cancellationToken = default)
	{
	if (MemoryMarshal.TryGetArray(buffer, out ArraySegment<byte> array))
	{
	return new ValueTask(WriteAsync(array.Array!, array.Offset, array.Count, cancellationToken));
	}
	byte[] sharedBuffer = ArrayPool<byte>.Shared.Rent(buffer.Length);
	buffer.Span.CopyTo(sharedBuffer);
	return new ValueTask(FinishWriteAsync(WriteAsync(sharedBuffer, 0, buffer.Length, cancellationToken), sharedBuffer));
	}

You can copy the default implementation in Stream to get a suboptimal implementation.

[GF-Huang]

This seems to be simple wrapper and one more redundant copy operation.

And I read the source of NetworkStream, it looks like pass the ReadOnlyMemory to the socket directly, not a wrapper.

https://source.dot.net/#System.Net.Sockets/System/Net/Sockets/NetworkStream.cs,e3c427161b014da6

[huoyaoyuan]

On netstandard2.0 you have no way to reduce the redundant copy. The BCL implementation was not that extensible.