[QUIC] QuicStream add ReadsCompleted

[CarnaViire]

Add ReadsCompleted API that exposes ReadState=ReadsCompleted, set ReadState to ReadsCompleted if FIN flag arrives in RECEIVE event, fix ReadState changing to final stauses, expand ReadState transition description

Fixes #55707

cc @JamesNK @Tratcher

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Issue Details

---

Add ReadsCompleted API that exposes ReadState=ReadsCompleted, set ReadState to ReadsCompleted if FIN flag arrives in RECEIVE event, fix ReadState changing to final stauses, expand ReadState transition description

Fixes #55707

cc @JamesNK @Tratcher

Author:	CarnaViire
Assignees:	-
Labels:	new-api-needs-documentation, area-System.Net.Quic
Milestone:	-

[Tratcher]

Unfinished test name?

[CarnaViire]

The name's like that because it is basically the same test as QuicStreamTests.BasicTest

runtime/src/libraries/System.Net.Quic/tests/FunctionalTests/QuicStreamTests.cs

Lines 23 to 55 in 42af636

	public async Task BasicTest()
	{
	await RunClientServer(
	iterations: 100,
	serverFunction: async connection =>
	{
	await using QuicStream stream = await connection.AcceptStreamAsync();
	byte[] buffer = new byte[s_data.Length];
	int bytesRead = await ReadAll(stream, buffer);
	Assert.Equal(s_data.Length, bytesRead);
	Assert.Equal(s_data, buffer);
	await stream.WriteAsync(s_data, endStream: true);
	await stream.ShutdownCompleted();
	},
	clientFunction: async connection =>
	{
	await using QuicStream stream = connection.OpenBidirectionalStream();
	await stream.WriteAsync(s_data, endStream: true);
	byte[] buffer = new byte[s_data.Length];
	int bytesRead = await ReadAll(stream, buffer);
	Assert.Equal(s_data.Length, bytesRead);
	Assert.Equal(s_data, buffer);
	await stream.ShutdownCompleted();
	}
	);
	}

But with added ReadsCompleted checks 😄
In your initial commit, you've added these checks to the BasicTest itself. But that makes it non-fully-basic then 😄 and it had flaky problems with Mock behavior. As we don't prioritize fixing Mock, I moved the test with checks to the test collection that only runs on MsQuic.

That being said, I have no strong feeling in sticking to the name BasicTest. So I can rename it to e.g. SendReceive_WithReadsCompletedCheck

[Tratcher]

Ah. I wasn't familiar with BasicTest so this name seemed non-descript. I'll let you decide what to do with it.

[adityamandaleeka]

Thanks @CarnaViire!

[karelz]

Browser runs are hitting #57501, unrelated to this PR.
Libraries test failures are test suites which were cut off (similar things are happening on other PRs). None of the test suites are related to Quic/Networking, so unrelated to this PR.

[CarnaViire]

Test failures are unrelated, so merging