As already mentioned, SPDY's new stream features made it possible for the server to push data to the client without responding to a client's request. This made communication bidirectional and allowed the web server to anticipate the needs of the client. Indeed, even before the client had done parsing the HTML and determined all the files that would be necessary in order to render the page, the web server could push the files down the stream to the client, thus reducing the number of requests sent by the client in order to fetch all the necessary resources:
How the 'server push' feature works
By knowing that many studies show ...
