I think dose not have radical change just add Asynchronously flushing a response
Asynchronously flushing a response
Sending responses to an HTTP client can take considerable time when
the client is far away or has a low-bandwidth connection. Normally
ASP.NET buffers the response bytes as they are created by an
application. ASP.NET then performs a single send operation of the
accrued buffers at the very end of request processing.
If the buffered response is large (for example, streaming a large file
to a client), you must periodically call HttpResponse.Flush to send
buffered output to the client and keep memory usage under control.
However, because Flush is a synchronous call, iteratively calling
Flush still consumes a thread for the duration of potentially
long-running requests.
ASP.NET 4.5 adds support for performing flushes asynchronously using
the BeginFlush and EndFlush methods of the HttpResponse class. Using
these methods, you can create asynchronous modules and asynchronous
handlers that incrementally send data to a client without tying up
operating-system threads. In between BeginFlush and EndFlush calls,
ASP.NET releases the current thread. This substantially reduces the
total number of active threads that are needed in order to support
long-running HTTP downloads.