Target a registered ServerCallback in any resource by setting the first parameter to that resource name, then utilise whatever event name you desire.
For my test, I utilised `test` and `testevent`, which registers an event with the name `__cb_test:testevent`.
The third parameter sets a delay for how often the client can trigger the callback (to prevent spam in certain situations).
There's also ServerCallback.Await which halts the thread and returns the values rather than using a callback (I haven't tested it since refactoring all this code, though).