Besides multiplexing, another powerful feature of HTTP/2 is its server push capability.
Mainly, in the traditional approach (HTTP/1.1), a browser triggers a request for getting an HTML page and parses the received markup to identify the referenced resources (for example, JS, CSS, images, and so on). To fetch these resources, the browser sends additional requests (one request for each referenced resource). On the other hand, HTTP/2 sends the HTML page and the referenced resources without explicit requests from the browser. So, the browser requests the HTML page and receives the page and everything else that's needed for displaying the page.
The HTTP Client API supports this HTTP/2 feature via the PushPromiseHandler ...
