Call load_document from js/browser

It looks like Session.poll_document just alternates between calling Session.load_document and time.sleep. Is there a way to trigger a load_document call from bokeh.js? It seems conceptually simpler to trigger that kind of call every time a widget is triggered or a glyph is selected rather than requiring the application to check the server every half a second. Also, poll_document only calls load_document, when in most cases I don’t want to load the whole document - I only want to load the object(s) that I’ve changed.

Any tips for implementing this kind of functionality? I’m happy to work on it if it’s not something that currently exists, but I’d appreciate any advice that could point me in the right direction.

Thanks in advance.