Attribute Macro auto_plugin 

#[auto_plugin]

Attaches to a fn and injects a call to the initialization function that automatically registering types, events, and resources in the App. Attribute to mark the build function for the plugin, or impl Plugin trait build method for injection

Parameters

• plugin = PluginType - Required for bare functions only. Specifies the plugin this build function belongs to.
  Not allowed on impl Plugin methods, since the plugin type is already known.
• app_param = identifier - (Optional) Specifies the name of the App parameter that code will be injected into.
  Defaults to app if omitted.

Example - impl Plugin

use bevy::prelude::*;
use bevy_auto_plugin::prelude::*;

#[derive(AutoPlugin)]
struct MyPlugin;

impl Plugin for MyPlugin {
    #[auto_plugin(app_param=non_default_app_param_name)]
    fn build(&self, non_default_app_param_name: &mut App) {
        // code injected here

        // your code
    }
}

Example - bare fn

use bevy::prelude::*;
use bevy_auto_plugin::prelude::*;

#[derive(AutoPlugin)]
struct MyPlugin;

#[auto_plugin(plugin = MyPlugin, app_param=non_default_app_param_name)]
fn build(non_default_app_param_name: &mut App) {
    // code injected here

    // your code
}