fix bug

Author: danielgerlag

src/Directory.Build.props

@@ -4,10 +4,10 @@
     <PackageLicenseUrl>https://github.com/danielgerlag/workflow-core/blob/master/LICENSE.md</PackageLicenseUrl>
     <RepositoryType>git</RepositoryType>
     <RepositoryUrl>https://github.com/danielgerlag/workflow-core.git</RepositoryUrl>
-    <Version>3.6.0</Version>
-    <AssemblyVersion>3.6.0.0</AssemblyVersion>
-    <FileVersion>3.6.0.0</FileVersion>
+    <Version>3.6.1</Version>
+    <AssemblyVersion>3.6.1.0</AssemblyVersion>
+    <FileVersion>3.6.1.0</FileVersion>
     <PackageIconUrl>https://github.com/danielgerlag/workflow-core/raw/master/src/logo.png</PackageIconUrl>
-    <PackageVersion>3.6.0</PackageVersion>
+    <PackageVersion>3.6.1</PackageVersion>
   </PropertyGroup>
 </Project>

src/WorkflowCore/Services/BackgroundTasks/RunnablePoller.cs

@@ -161,6 +161,9 @@ private async Task PollCommands()
         {
             try
             {
+                if (!_persistenceStore.SupportsScheduledCommands)
+                    return;
+
                 if (await _lockProvider.AcquireLock("poll-commands", new CancellationToken()))
                 {
                     try