Reimplement HttpRequestStreamReader and HttpResponseStreamWriter with pipes

[jkotalik]

Epic #8829

Most likely this will be done via two new classes: PipeTextReader and PipeTextWriter. These are implementations of TextReader/TextWriter that take in a PipeReader/PipeWriter as a constructor argument.

[alefranz]

I've been looking at something to work on and @rynowak has pointed me to this.
I've experimented a bit with this and created a really basic prototype.
If this is still it up for grabs I would like to start to work on a PR.

@JamesNK is this already on your radar as part of #13750?

I was thinking of introducing a HttpResponseStreamWriter that implement TextWriter to handle encoding and write to a pipe.
Does it also needs to be buffered, so to avoid requesting a large buffer (over a configured value) to the underling Pipe and use multiple FlushAsync(), as well as avoiding FlushAsync() for small writes?

Main goal would be to use this from MVC to render the view.

Thank you!

/cc @davidfowl