Expect doesn't wake up after disconnect

[sterlind]

If the connection is lost while we're waiting in ShellStream.Expect(), Expect() doesn't wake up, either hanging forever or until the timeout elapses.

Here's a simple repro. I configured the target server (a Cisco NCS-5K) to end sessions that have been idle for 30 seconds, and then I set an expect that never matches. The connection dies 30 seconds in, but the Supercalifragilisticexpialidocious Expect waits 5 excruciating minutes to return:

 var ssh = new SshClient(info);
 ssh.Connect();
 using (var shell = ssh.CreateShellStream("xterm", 80, 80, 80, 80, 1024))
 {
 shell.Expect("#", TimeSpan.FromSeconds(30));
 Trace.TraceInformation("Shell has started!");
 var time = Stopwatch.StartNew();
 var result = shell.Expect("Supercalifragilisticexpialidocious!", TimeSpan.FromMinutes(5));
 Trace.TraceInformation($"Shell took {time.Elapsed} to time out..");
 }

Expect() should return immediately upon disconnect.

[WojciechNagorski]

It's done in #1274

[WojciechNagorski]

The 2023.0.1 version has been released to Nuget: https://www.nuget.org/packages/SSH.NET/2023.0.1