fix(websockets): Initialise io_loop in multi-worker environments

[quartzar]

Problem Addressed

This PR addresses the issue where WebSocket connections frequently fail when running a Django application with Bokeh integration using multiple Gunicorn workers. In multi-worker environments, there was only a 1/n chance (where n is the number of workers) that the WebSocket connection would succeed.

Solution

The solution implements a more robust approach to io_loop initialisation by:

1. Explicitly setting the io_loop using IOLoop.current() if it doesn't exist
2. Ensuring the io_loop is set before attempting session creation
3. Adding defensive coding in the disconnect method

This change removes the worker affinity requirement, allowing any worker to successfully handle WebSocket connections regardless of which worker handled the initial HTTP request.

Changes Made

• Modified WSConsumer.application_context to initialise the io_loop rather than raising an error
• Ensured proper io_loop initialisation before session creation
• Misc: Fixed a deprecation and added await to some un-awaited coroutines

Testing

Tested with Gunicorn running with 4 Uvicorn workers, confirming:

• Before fix: ~25% success rate for Bokeh autoload app loading
• After fix: 100% success rate for Bokeh autoload app loading

Closes #15