public static <T> T createMulticaster(@NotNull Class<T> listenerClass,
                                        @NotNull Supplier<? extends Iterable<T>> listeners) {
    return createMulticaster(listenerClass, null, listeners);
  }
public static <T> T createMulticaster(@NotNull Class<T> listenerClass,
                                        @NotNull Supplier<? extends Iterable<T>> listeners)