Edited Issue: TransferEncodingChunked=true doesn't work on WebHost [1124]

When setting response.Headers.TransferEncodingChunked, the response doesn't get chunked, and a client (Fiddler) will fail trying to read the response.

Repro 1:
public HttpResponseMessage Get()
{
HttpResponseMessage response = new HttpResponseMessage(HttpStatusCode.OK);
response.Headers.TransferEncodingChunked = true;
response.RequestMessage = Request;
return response;
}

Repro 2:
public HttpResponseMessage Get()
{
HttpResponseMessage response = new HttpResponseMessage(HttpStatusCode.OK);
response.Content = new LazyContent();
response.Headers.TransferEncodingChunked = true;
response.RequestMessage = Request;
return response;
}

public class LazyContent : HttpContent
{
protected override Task SerializeToStreamAsync(Stream stream, TransportContext context)
{
stream.WriteByte(0);
return Task.FromResult<object>(null);
}

protected override bool TryComputeLength(out long length)
{
length = 0;
return false;
}
}