The HTTP server no longer immediately sends response headers if chunked mode is selected or if the response has a body. The previous behavior had the effect of slowing down response times due to delayed acknowledgments on some operating systems. With this change, the headers will be buffered and sent with the response body if one is expected. This should result in improved performance for certain kinds of responses. Note, it is advisable now to always close the HTTP exchange or response body stream to force the sending of the response headers and is required in all cases except where there is no response body.