One of the biggest missed opportunities thus far with HTTP/2 ("H/2") is that we are not yet able to sunset WebSockets in favor of H/2. Web Sockets and H/2 both support multiplexing messages bi-directionally and can send both textual and binary data.
Server Sent Events ("SSE"), by contrast, are not bi-directional (they're a "server-push-only" channel) and binary data cannot be sent easily. They are, however, very simple to implement. Adding to the menagerie of options, RTCPeerConnection can also be used to signal data to applications in a low-latency (but potentially lossy) way.
Because H/2 [does not support the handshake (upgrade) that WebSockets use to negotiate a connection](https://daniel.haxx.se/blog/2016/06/15/no-websockets-