add comments to code

Author: egil

src/bunit.core/Extensions/WaitForHelpers/WaitForHelper.cs

@@ -48,9 +48,9 @@ protected WaitForHelper(
 	{
 		this.renderedFragment = renderedFragment ?? throw new ArgumentNullException(nameof(renderedFragment));
 		this.completeChecker = completeChecker ?? throw new ArgumentNullException(nameof(completeChecker));
+
 		logger = renderedFragment.Services.CreateLogger<WaitForHelper<T>>();
 		checkPassedCompletionSource = new TaskCompletionSource<T>();
-
 		WaitTask = CreateWaitTask(renderedFragment, timeout);
 
 		InitializeWaiting();
@@ -80,8 +80,8 @@ protected virtual void Dispose(bool disposing)
 			return;
 
 		isDisposed = true;
-		checkPassedCompletionSource.TrySetCanceled();
 		renderedFragment.OnAfterRender -= OnAfterRender;
+		checkPassedCompletionSource.TrySetCanceled();
 		logger.LogWaiterDisposed(renderedFragment.ComponentId);
 	}
 
@@ -175,6 +175,9 @@ private void OnAfterRender(object? sender, EventArgs args)
 
 	private void SubscribeToOnAfterRender()
 	{
+		// There might not be a need to subscribe if the WaitTask has already
+		// been completed, perhaps due to an unhandled exception from the
+		// renderer or from the initial check by the checker.
 		if (!isDisposed && !WaitTask.IsCompleted)
 			renderedFragment.OnAfterRender += OnAfterRender;
 	}