Calling Open on ICommunication leaves async timer running which closes socket.

[peteri]

Describe the bug
If Open is called on a netTcp connection (unsure about other types) then if a ServiceContract method is invoked AFTER the open time has expired then the socket will have been closed.

This appears to be due the BeginWriteCore method in SocketConnection.cs starting an timer for asynchronous send operations. The EndWrite method does not cancel the _sendTimer which expires and closes the socket.

Calling a method sends synchronously which calls SetWriteTimeout with synchronous set to true. SetWriteTimeout then clears the _sendTimer by cancelling it.

I believe this is new as the calls to System.Net.NegotiateStream is now async (comparing to the reference source code)

To Reproduce
Add and run the test in this commit (I used Binding.Tcp.IntegrationTests)
peteri@cd6d1f1

Apologies for the "hacky" nature of this as I can't build the current master so tested on the release/2.1.0 branch and the Thread.Sleep.

Expected behavior
Calling Open does not abort the connection.

[peteri]

Reference source code version ends up calling this code:
https://github.com/microsoft/referencesource/blob/3b1eaf5203992df69de44c783a3eda37d3d4cd10/System/net/System/Net/SecureProtocols/_NegoStream.cs

[StephenBonikowsky]

@peteri Thanks for reporting this! We will target this fix for the next release before the end of the year.

[peteri]

Sorry about the test being quite so crappy (I hate using Thread.Sleep) but at least it gives you something to work with.

[mconnew]

@peteri, I think you can make test methods async and do await Task.Delay(1000) instead.

[StephenBonikowsky]

Potentially fixed by #3994

[StephenBonikowsky]

The PR has been merged, the change will be part of 3.1 preview3 which will be released sometime in November.