Fix net incompatibilities

Author: danielmarbach

projects/Test/Applications/CreateChannel/CreateChannel.csproj

@@ -14,6 +14,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
+    <LangVersion>9.0</LangVersion>
   </PropertyGroup>
 
   <ItemGroup>

projects/Test/Integration/TestAsyncConsumer.cs

@@ -614,7 +614,7 @@ public async Task TestCreateChannelWithinAsyncConsumerCallback_GH650()
 
             var tcs = new TaskCompletionSource<bool>(TaskCreationOptions.RunContinuationsAsynchronously);
             using var cts = new CancellationTokenSource(WaitSpan);
-            await using CancellationTokenRegistration ctr = cts.Token.Register(() =>
+            using CancellationTokenRegistration ctr = cts.Token.Register(() =>
             {
                 tcs.SetCanceled();
             });

projects/Test/Integration/TestBasicPublish.cs

@@ -174,7 +174,7 @@ public async Task TestMaxInboundMessageBodySize()
         {
             var tcs = new TaskCompletionSource<bool>(TaskCreationOptions.RunContinuationsAsynchronously);
             using var cts = new CancellationTokenSource(WaitSpan);
-            await using CancellationTokenRegistration ctr = cts.Token.Register(() => tcs.SetCanceled());
+            using CancellationTokenRegistration ctr = cts.Token.Register(() => tcs.SetCanceled());
 
             const ushort maxMsgSize = 8192;
 

projects/Test/SequentialIntegration/TestConnectionBlockedChannelLeak.cs

@@ -65,7 +65,7 @@ public async Task TestConnectionBlockedChannelLeak_GH1573()
             var connectionUnblockedTcs = new TaskCompletionSource<bool>(TaskCreationOptions.RunContinuationsAsynchronously);
 
             using var cts = new CancellationTokenSource(WaitSpan);
-            await using CancellationTokenRegistration ctr = cts.Token.Register(() =>
+            using CancellationTokenRegistration ctr = cts.Token.Register(() =>
             {
                 connectionBlockedTcs.TrySetCanceled();
                 connectionUnblockedTcs.TrySetCanceled();