@Nonnull
    static <T> MergedSubscriptionBuilder<T> newBuilder(@Nonnull Class<T> handledClass) {
        Objects.requireNonNull(handledClass, "handledClass");
        return new MergedSubscriptionBuilderImpl<>(TypeToken.of(handledClass));
    }
Makes a MergedHandlerBuilder for a given super type

@param handledClass the super type of the event handler
@param <T>          the super type class
@return a {@link MergedSubscriptionBuilder} to construct the event handler
helper/src/main/java/me/lucko/helper/event/functional/merged/MergedSubscriptionBuilder.java