added a Disposed check and Debug Message to prevent enqueing messages after the Generic Queue has been disposed; typically happens at program stop

Hotfix/scheduler fixes

.github/workflows/docker.yml

@@ -58,7 +58,7 @@ jobs:
       - name: Build Solution
         shell: powershell
         run: |
-          Invoke-Expression "docker run --rm --mount type=bind,source=""$($Env:GITHUB_WORKSPACE)"",target=""c:/project"" pepperdash/sspbuilder:dev c:\cihelpers\vsidebuild.exe -Solution ""c:\project\$($Env:SOLUTION_FILE).sln"" -BuildSolutionConfiguration $($ENV:BUILD_TYPE)"
+          Invoke-Expression "docker run --rm --mount type=bind,source=""$($Env:GITHUB_WORKSPACE)"",target=""c:/project"" pepperdash/sspbuilder c:\cihelpers\vsidebuild.exe -Solution ""c:\project\$($Env:SOLUTION_FILE).sln"" -BuildSolutionConfiguration $($ENV:BUILD_TYPE)"
       # Zip up the output files as needed
       - name: Zip Build Output
         shell: powershell

essentials-framework/Essentials Core/PepperDashEssentialsBase/Queues/GenericQueue.cs

@@ -199,6 +199,12 @@ namespace PepperDash.Essentials.Core.Queues
 
         public void Enqueue(IQueueMessage item)
         {
+            if (Disposed)
+            {
+                Debug.Console(1, this, "I've been disposed so you can't enqueue any messages.  Are you trying to dispatch a message while the program is stopping?");
+                return;
+            }
+
             _queue.Enqueue(item);
             _waitHandle.Set();
         }