Remove bad IsCompleted Check

src/Servers/Kestrel/Core/src/Internal/Http2/Http2Stream.cs

@@ -368,11 +368,16 @@ public Task OnDataAsync(Http2Frame dataFrame, ReadOnlySequence<byte> payload)
                         {
                             RequestBodyPipe.Writer.Write(segment.Span);
                         }
-                        var flushTask = RequestBodyPipe.Writer.FlushAsync();
 
-                        // It shouldn't be possible for the RequestBodyPipe to fill up an return an incomplete task if
-                        // _inputFlowControl.Advance() didn't throw.
-                        Debug.Assert(flushTask.IsCompleted);
+                        // If the stream is completed go ahead and call RequestBodyPipe.Writer.Complete().
+                        // Data will still be available to the reader.
+                        if (!endStream)
+                        {
+                            var flushTask = RequestBodyPipe.Writer.FlushAsync();
+                            // It shouldn't be possible for the RequestBodyPipe to fill up an return an incomplete task if
+                            // _inputFlowControl.Advance() didn't throw.
+                            Debug.Assert(flushTask.IsCompleted);
+                        }
                     }
                 }
             }

src/Servers/Kestrel/test/InMemory.FunctionalTests/Http2/Http2StreamTests.cs

@@ -1021,8 +1021,8 @@ public async Task ContentLength_Received_ReadViaPipes()
             await InitializeConnectionAsync(async context =>
             {
                 var readResult = await context.Request.BodyPipe.ReadAsync();
-                Assert.Equal(12, readResult.Buffer.Length);
                 Assert.True(readResult.IsCompleted);
+                Assert.Equal(12, readResult.Buffer.Length);
                 context.Request.BodyPipe.AdvanceTo(readResult.Buffer.End);
 
                 readResult = await context.Request.BodyPipe.ReadAsync();