Project link on github: https://github.com/CrowdHailer/watercooler
When viewing this application over https content will be served over a single connection using the HTTP/2 protocol. One of the streams is used to stream server sent events from server to client. At this point both client and server can freely send messages to the other. Bidirectionally communication is achieved using a single TCP connection.
The need for bidirectional communication was the motivation for websockets in HTTP/1.
However because a stream of server sent events can share a connection with other requests from client to server there are very few reasons to keep using websockets with HTTP/2.