add call_for_blog for easy to switch blog and restore in multisite

[denishua]

add call_for_blog for easy to switch blog and restore in multisite

function call_for_blog($blog_id, $callback, ...$args){
	try{
		$switched	= (is_multisite() && $blog_id && $blog_id != get_current_blog_id()) ? switch_to_blog($blog_id) : false;

		return call_user_func_array($callback, $args);
	}finally{
		if($switched){
			restore_current_blog();
		}
	}
}

usage:

call_for_blog(123, 'wp_update_post', ['ID'=>$id, 'post_title'=>$title]);

closure callback:

for_blog($shop_blog_id, function($id, $title){
	$result	= some_function();

	if(is_wp_error($result)){
		return $result;
	}

	$result	= some_other_function();

	if(is_wp_error($result)){
		return $result;
	}

	return wp_update_post(['ID'=>$id, 'post_title'=>$title]);	
}, $id, $title);