I must keep certain track to ensure messages from one user makes it to an entire room or a specific
I must keep certain track to ensure messages from one user makes it to an entire room or a specific user's inbox while in session.

addEventListener means you are in service worker formatexport default { fetch } means you are in module formatenv.KV where env is the second parameter of the fetch function.
env.KVenvexport default {
async fetch(request, env) {
const setCache = (key, data) => env.EXAMPLE_TODOS.put(key, data);
const getCache = key => env.EXAMPLE_TODOS.get(key);
}
};