lib-nested/nested/src/core/view.rs

                    /*\
<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
                   View
<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>
                    \*/
pub trait View : Send + Sync {
    /// Notification message for the observers
    type Msg : Send + Sync;
}

//<<<<>>>><<>><><<>><<<*>>><<>><><<>><<<<>>>>

use std::sync::Arc;
use std::sync::RwLock;

impl<V: View + ?Sized> View for RwLock<V> {
    type Msg = V::Msg;
}

impl<V: View + ?Sized> View for Arc<V> {
    type Msg = V::Msg;
}

impl<V: View> View for Option<V> {
    type Msg = V::Msg;
}