Merge pull request #16556 from jtattermusch/csharp_expose_trywaitforstatechanged

C#: Expose TryWaitForStateChangedAsync

src/csharp/Grpc.Core.Tests/ChannelConnectivityTest.cs

@@ -57,19 +57,23 @@ namespace Grpc.Core.Tests
         [Test]
         public async Task Channel_WaitForStateChangedAsync()
         {
-            helper.UnaryHandler = new UnaryServerMethod<string, string>((request, context) =>
-            {
-                return Task.FromResult(request);
-            });
-
             Assert.ThrowsAsync(typeof(TaskCanceledException), 
-                async () => await channel.WaitForStateChangedAsync(channel.State, DateTime.UtcNow.AddMilliseconds(10)));
+                async () => await channel.WaitForStateChangedAsync(channel.State, DateTime.UtcNow.AddMilliseconds(0)));
 
             var stateChangedTask = channel.WaitForStateChangedAsync(channel.State);
+            await channel.ConnectAsync(DateTime.UtcNow.AddMilliseconds(5000));
+            await stateChangedTask;
+            Assert.AreEqual(ChannelState.Ready, channel.State);
+        }
 
-            await Calls.AsyncUnaryCall(helper.CreateUnaryCall(), "abc");
+        [Test]
+        public async Task Channel_TryWaitForStateChangedAsync()
+        {
+            Assert.IsFalse(await channel.TryWaitForStateChangedAsync(channel.State, DateTime.UtcNow.AddMilliseconds(0)));
 
-            await stateChangedTask;
+            var stateChangedTask = channel.TryWaitForStateChangedAsync(channel.State);
+            await channel.ConnectAsync(DateTime.UtcNow.AddMilliseconds(5000));
+            Assert.IsTrue(await stateChangedTask);
             Assert.AreEqual(ChannelState.Ready, channel.State);
         }
 

src/csharp/Grpc.Core/Channel.cs

@@ -136,7 +136,7 @@ namespace Grpc.Core
         /// </summary>
         public async Task WaitForStateChangedAsync(ChannelState lastObservedState, DateTime? deadline = null)
         {
-            var result = await WaitForStateChangedInternalAsync(lastObservedState, deadline).ConfigureAwait(false);
+            var result = await TryWaitForStateChangedAsync(lastObservedState, deadline).ConfigureAwait(false);
             if (!result)
             {
                 throw new TaskCanceledException("Reached deadline.");
@@ -147,7 +147,7 @@ namespace Grpc.Core
         /// Returned tasks completes once channel state has become different from
         /// given lastObservedState (<c>true</c> is returned) or if the wait has timed out (<c>false</c> is returned).
         /// </summary>
-        internal Task<bool> WaitForStateChangedInternalAsync(ChannelState lastObservedState, DateTime? deadline = null)
+        public Task<bool> TryWaitForStateChangedAsync(ChannelState lastObservedState, DateTime? deadline = null)
         {
             GrpcPreconditions.CheckArgument(lastObservedState != ChannelState.Shutdown,
                 "Shutdown is a terminal state. No further state changes can occur.");