Port, redirect and modernize all .NET networking content.

[IEvangelist]

Port, redirect and modernize all .NET networking content. There is a whole sub-doc-set located here:

• Network Programming in the .NET Framework

Much of this content is severely out-of-date, and many code examples reference obsolete APIs. The strategy is to move (port) conceptual content from the Network Programming in the .NET Framework under the modern .NET Fundamentals / Runtime Libraries / Networking TOC:

We should converge the existing HTTP-specific content under a new TOC node, .NET Fundamentals / Runtime Libraries / Networking / HTTP. Then we should create several new nodes to capture content specific to additional protocols, such as TCP, UDP, FTP, WebSockets, and whatever else I might be missing. A lot of the legacy content specific to .NET Framework can be modernized and code samples updated accordingly.

Asynchronous patterns such as:

• Begin{X} / End{X}
• AsyncCallback
• IAsyncResult

Should be removed in favor of, async/await, Task, and ValueTask (or other task-like alternatives). conceptual rewrites should strive to serve new learned audiences, making adoption easy.

/cc @richlander

[richlander]

This looks great and has very high value. Turns out that modern scenarios require a lot of networking, right?

Some things to consider (likely as advanced scenarios; unordered):

• Sync over async
• Transport-agnostic APIs (both producing and consuming)
• How to wrap those old async patterns. I agree we don't want folks producing new code that uses those patterns, but interacting with them may still be required for some scenarios.
• Using all the modern networking patterns like circuit breakers. If those are not available in-box, which libraries should folks use to take advantage of those.
• How to handle flaky networkings, including cellular
• Are there any scenarios where .NET devs need to reason about LTE vs 5G for cell links?
• Networking in containers
• Global vs local DNS (including sidecars)
• Unix domain sockets vs DNS
• HTTPS/TLS termination
• When to use HTTP, HTTPS, HTTP/2, HTTP/3 (and which capabilities are (not) supported for each, if relevant). AFAIK, there are valid use cases for all of these. For example, I know some folks terminate TLS at the load balancer (if that's the correct term) and then use raw HTTP between nodes. There are pros and cons with that.
• ValueTask should probably be considered an advanced scenario. Would be good to validate that.
• Stream vs Pipelines

@davidfowl

[IEvangelist]

We do have coverage of Pipelines, and it is discussed in the context of I/O and streams:

• System.IO.Pipelines in .NET