Support cancellation of NodeServices invocations

src/Microsoft.AspNetCore.NodeServices/Util/TaskExtensions.cs

@@ -0,0 +1,30 @@
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace Microsoft.AspNetCore.NodeServices
+{
+    internal static class TaskExtensions
+    {
+        public static Task OrThrowOnCancellation(this Task task, CancellationToken cancellationToken)
+        {
+            return task.IsCompleted
+                ? task // If the task is already completed, no need to wrap it in a further layer of task
+                : task.ContinueWith(
+                    _ => {}, // If the task completes, allow execution to continue
+                    cancellationToken,
+                    TaskContinuationOptions.ExecuteSynchronously,
+                    TaskScheduler.Default);
+        }
+
+        public static Task<T> OrThrowOnCancellation<T>(this Task<T> task, CancellationToken cancellationToken)
+        {
+            return task.IsCompleted
+                ? task // If the task is already completed, no need to wrap it in a further layer of task
+                : task.ContinueWith(
+                    t => t.Result, // If the task completes, pass through its result
+                    cancellationToken,
+                    TaskContinuationOptions.ExecuteSynchronously,
+                    TaskScheduler.Default);
+        }
+    }
+}