...
private void OnWheel(Event mouseEvent) { ... }
...
// OnWheelEvent is Action<Event>
OnWheelEvent = EventInvoker.From(OnWheel);
...

static class EventInvoker {
    public static Action<T> From<T>(Action<T> action) ...
}

error CS0411: The type arguments for method 'EventInvoker.From<T>(Action<T>)' cannot be inferred from the usage. Try specifying the type arguments explicitly.