Hi,
At present, only the JavaScript client libraries (for both web browsers and Node) use WebSockets, in addition to HTTP, while the other libraries use HTTP only. But support for WebSocket in the other libs, starting from Java, is on the go. This will be completely transparent to the application code, as the API doesn't change.
Consider that WebSockets are better than HTTP Streaming only for sending high-frequency messages FROM the client to the SERVER (see
this slide).