code: public static <S, T extends Event> InputMapTemplate<S, T> process(
              EventType<? extends T> eventType,
              BiFunction<? super S, ? super T, InputHandler.Result> action) {
          return process(EventPattern.eventType(eventType), action);
      }
docs: When the given event type occurs, runs the given action, and then attempts
  to pattern match the event type with the next {@code InputMap} (if one exists).