avoid GCHandle in ConnectEx and SendTo on Windows

[wfurt]

SocketAddress needs to be preserved only for initial call of ConnextEx and SendTo. There is no need to allocate GCHandle (and hold do it through connection time)

AFAIK interop should now generate fixed automatically for Span so we can simply pass it in.

This helps to avoid memory fragmentation through small pinned buffers and contributes to #86513 and #30797.

I will follow up on ReceiveFrom separatelly as this part at least fixes TCP and issue observed by customer.

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Issue Details

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SocketAddress needs to be preserved only for initial call of ConnextEx and SendTo. There is no need to allocate GCHandle (and hold do it through connection time)

AFAIK interop should now generate fixed automatically for Span so we can simply pass it in.

This helps to avoid memory fragmentation through small pinned buffers and contributes to #86513 and #30797.

I will follow up on ReceiveFrom separatelly as this part at least fixes TCP and issue observed by customer.

Author:	wfurt
Assignees:	wfurt
Labels:	area-System.Net.Sockets, os-windows
Milestone:	8.0.0

[stephentoub]

Nice.