Custom encoders for WebSocket payloads

[lifeiscontent]

Feature request

Is your feature request related to a problem? Please describe.

would be ideal to have alternatives to receiving messages via WebSockets

Describe the solution you'd like

if possible the ability to pass custom coder functions for encoding and decoding messages rather than just JSON

Describe alternatives you've considered

N/A

Additional context

BSON is my first thought here, but if you could manage to add support for custom coders that would be even better because it'd open more alternatives to how a client receives messages.

[chasers]

@lifeiscontent I updated the title here to better reflect your request. We'll take a closer look.