Macro mf_plugin_config 

macro_rules! mf_plugin_config {
    () => { ... };
    (enabled = $enabled:expr, priority = $priority:expr) => { ... };
    (enabled = $enabled:expr, priority = $priority:expr, settings = { $($key:expr => $value:expr),* $(,)? }) => { ... };
}

创建插件配置的辅助宏