Check HubConnection state before running invoke logic

[mikaelm12]

Before calling methods that require the HubConnection to be connected we run a simple connection state check like
https://github.com/aspnet/AspNetCore/blob/e310ccac7b30e901f657f81c86c4048fecfedf7b/src/SignalR/clients/java/signalr/src/main/java/com/microsoft/signalr/HubConnection.java#L464-L466

Addresses #4393

Description

Before being able to send invocations from a SignalR hub, it's important that we ensure that the current HubConnection is active and in the connected state. If the HubConnection isn't connected we should fail immediately without attmepting to send any invocations. Otherwise we could run into a case where users can write the connected

HubConnection hubConnection = new HubConnectionBuilder.create("Some hub url");
// There should be an awaited call to start before invoke.
hubConnection.invoke(String.class, "hubMethod", "arg")

Customer Impact

With this change, when a customer tries to invoke a hub method when their client is not connected, they will get a helpful error message letting them know that they are in the disconnected state.

Regression

N/A

Risk

Low. This is purely a defensive change. We woul be adding a check to the HubConnection state before continuing to the rest of the invoke logic to ensure that we fail fast with a helpful error message. This also has an associate test.

[muratg]

@mikaelm12 can you also add the shiproom template? (You can find a copy from #4403)

[mikaelm12]

Added the template

[vivmishra]

Approved for 2.2.2

[muratg]

Buid checks seem to be failing.

[mikaelm12]

The failure was for an IIS Functional test. An unrelated test failure.

Starting test execution, please wait...
2018-12-04T22:55:50.8997274Z   [xUnit.net 00:00:17.97]     Microsoft.AspNetCore.Server.IIS.FunctionalTests.AppOfflineTests.AppOfflineDroppedWhileSiteFailedToStartInRequestHandler_SiteStops_InProcess [SKIP]
2018-12-04T22:55:51.8627524Z   Skipped  Microsoft.AspNetCore.Server.IIS.FunctionalTests.AppOfflineTests.AppOfflineDroppedWhileSiteFailedToStartInRequestHandler_SiteStops_InProcess
2018-12-04T22:57:20.4801986Z   [xUnit.net 00:01:47.51]     Microsoft.AspNetCore.Server.IIS.FunctionalTests.AppOfflineTests.AppOfflineDroppedWhileSiteStarting_SiteShutsDown_InProcess [FAIL]
2018-12-04T22:57:20.4848481Z   Failed   Microsoft.AspNetCore.Server.IIS.FunctionalTests.AppOfflineTests.AppOfflineDroppedWhileSiteStarting_SiteShutsDown_InProcess
2018-12-04T22:57:20.4848649Z   Error Message:
2018-12-04T22:57:20.4848762Z    Assert.Equal() Failure
2018-12-04T22:57:20.4848871Z   Expected: 0
2018-12-04T22:57:20.4848956Z   Actual:   -1073740767

[dougbu]

Not sure how we ship our Java binaries. If necessary, please update the 2.2.2 section of eng/PatchConfig.props: https://github.com/aspnet/Extensions/blob/d8407116d183debaadb801c0cbc41d65927999d6/eng/PatchConfig.props#L7-L10

[mikaelm12]

@natemcmaster This look okay?

[natemcmaster]

Yes. Double check artifacts/ for the .jar file to make sure it worked.