update

Author: jkotalik

src/Servers/Kestrel/Core/src/Internal/Http/Http1OutputProducer.cs

@@ -538,7 +538,7 @@ private Memory<byte> GetChunkedMemory(int sizeHint)
             }
 
             var memoryMaxLength = _currentChunkMemory.Length - BeginChunkLengthMax - EndChunkLength;
-            if (_advancedBytesForChunk >= memoryMaxLength - sizeHint)
+            if (_advancedBytesForChunk >= memoryMaxLength - sizeHint && _advancedBytesForChunk > 0)
             {
                 // Chunk is completely written, commit it to the pipe so GetMemory will return a new chunk of memory.
                 var writer = new BufferWriter<PipeWriter>(_pipeWriter);

src/Servers/Kestrel/test/InMemory.FunctionalTests/ChunkedResponseTests.cs

@@ -920,7 +920,7 @@ public async Task GetMemoryWithSizeHintWithoutStartAsync()
                 Assert.Equal(4096, memory.Length);
 
                 memory = response.BodyWriter.GetMemory(1000000);
-                Assert.Equal(4096, memory.Length);
+                Assert.Equal(1000000, memory.Length);
                 await Task.CompletedTask;
             }, testContext))
             {