Initialize HttpConnectionManager before registering callbacks (#2878)

src/Microsoft.AspNetCore.Http.Connections/Internal/HttpConnectionManager.cs

@@ -10,7 +10,6 @@ using System.IO;
 using System.IO.Pipelines;
 using System.Net.WebSockets;
 using System.Security.Cryptography;
-using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.AspNetCore.Internal;
@@ -36,9 +35,11 @@ namespace Microsoft.AspNetCore.Http.Connections.Internal
         {
             _logger = loggerFactory.CreateLogger<HttpConnectionManager>();
             _connectionLogger = loggerFactory.CreateLogger<HttpConnectionContext>();
+            _nextHeartbeat = new TimerAwaitable(_heartbeatTickRate, _heartbeatTickRate);
+
+            // Register these last as the callbacks could run immediately
             appLifetime.ApplicationStarted.Register(() => Start());
             appLifetime.ApplicationStopping.Register(() => CloseConnections());
-            _nextHeartbeat = new TimerAwaitable(_heartbeatTickRate, _heartbeatTickRate);
         }
 
         public void Start()

test/Microsoft.AspNetCore.Http.Connections.Tests/HttpConnectionManagerTests.cs

@@ -314,6 +314,29 @@ namespace Microsoft.AspNetCore.Http.Connections.Tests
             await tcs.Task.OrTimeout();
         }
 
+        [Fact]
+        public async Task ApplicationLifetimeCanStartBeforeHttpConnectionManagerInitialized()
+        {
+            var appLifetime = new TestApplicationLifetime();
+            appLifetime.Start();
+
+            var connectionManager = CreateConnectionManager(appLifetime);
+            var tcs = new TaskCompletionSource<object>();
+
+            var connection = connectionManager.CreateConnection(PipeOptions.Default, PipeOptions.Default);
+
+            connection.Application.Output.OnReaderCompleted((error, state) =>
+            {
+                tcs.TrySetResult(null);
+            },
+            null);
+
+            appLifetime.StopApplication();
+
+            // Connection should be disposed so this should complete immediately
+            await tcs.Task.OrTimeout();
+        }
+
         private static HttpConnectionManager CreateConnectionManager(IApplicationLifetime lifetime = null)
         {
             lifetime = lifetime ?? new EmptyApplicationLifetime();