Macro define_plugin_internal 

macro_rules! define_plugin_internal {
    ($app:ident,) => { ... };
    ($app:ident, resources: [$($resource:ty),* $(,)?] $(, $($rest:tt)*)?) => { ... };
    ($app:ident, events: [$($event:ty),* $(,)?] $(, $($rest:tt)*)?) => { ... };
    ($app:ident, plugins: [$($plugin:expr),* $(,)?] $(, $($rest:tt)*)?) => { ... };
    ($app:ident, states: [$($state:ty),* $(,)?] $(, $($rest:tt)*)?) => { ... };
    ($app:ident, sub_states: [$($state:ty),* $(,)?] $(, $($rest:tt)*)?) => { ... };
    ($app:ident, reflect: [$($reflect_type:ty),* $(,)?] $(, $($rest:tt)*)?) => { ... };
    ($app:ident, startup: [$($system:expr),* $(,)?] $(, $($rest:tt)*)?) => { ... };
    ($app:ident, update: [$($system:expr),* $(,)?] $(, $($rest:tt)*)?) => { ... };
    ($app:ident, fixed_update: [$($system:expr),* $(,)?] $(, $($rest:tt)*)?) => { ... };
    ($app:ident, on_enter: { $($state:expr => [$($system:expr),* $(,)?]),* $(,)? } $(, $($rest:tt)*)?) => { ... };
    ($app:ident, on_exit: { $($state:expr => [$($system:expr),* $(,)?]),* $(,)? } $(, $($rest:tt)*)?) => { ... };
    ($app:ident, custom_init: $init_fn:expr $(, $($rest:tt)*)?) => { ... };
    ($app:ident, custom_finish: $finish_fn:expr $(, $($rest:tt)*)?) => { ... };
    ($app:ident, $unknown:tt $($rest:tt)*) => { ... };
}

Internal macro for parsing and applying plugin configuration. This is separate from the main macro to allow for recursive parsing.