EventListenerRepository

Where listeners are registered and removed. The handle you get back is the only way to unregister precisely.

api.events().repository()
Signature	Description
`RegisteredListener<T> register(Class<T>, Consumer<T>)`	Normal priority, receives cancelled events too.
`RegisteredListener<T> register(Class<T>, Consumer<T>, EventPriority)`	Normal semantics with an explicit ordering.
`RegisteredListener<T> register(Class<T>, Consumer<T>, EventPriority, boolean ignoreCancelled)`	Full form.
`void unregister(RegisteredListener<?> listener)`	Removes one listener and marks its handle inactive.
`void unregisterAll()`	Removes every listener registered through the API, including other plugins’ own.
`int listenerCount(Class<? extends VenusApiEvent>)`	How many listeners are registered for a type.

The handle

RegisteredListener is a small immutable record plus an active flag:

package xyz.kaosmc.anticheat.api.event
Signature	Description
`UUID id()`	Unique per registration, useful for logging.
`Class<T> eventClass()`	The class the listener was registered for.
`Consumer<? super T> consumer()`	The callback itself.
`EventPriority priority()`	Ordering priority.
`boolean ignoreCancelled()`	Whether cancelled events are skipped.
`boolean active()`	False once unregistered.
`void unregister()`	Marks the handle inactive without touching the repository.

private RegisteredListener<ViolationEvent> violationListener;

void onApi(VenusApi api) {
    violationListener = api.events().repository().register(
            ViolationEvent.class,
            event -> metrics.record(event.check().stableKey(), event.violationLevel()),
            EventPriority.RUN_FIRST,
            false);
}

void shutdown(VenusApi api) {
    if (violationListener != null) {
        api.events().repository().unregister(violationListener);
        violationListener = null;
    }
}

Notes

A listener registered for a supertype receives events of every subtype. Registering for UserCancellableEvent gives you everything a user did; registering for ViolationEvent gives you only flags.
unregisterAll() is a blunt instrument — it clears the whole repository. Use it only in a shutdown path you own.
Callbacks run on the thread that dispatched the event. Keep them short; heavy work belongs on your own executor.

Ordering is described on EventPriority; the events themselves are on event classes.