Function wayland_client::downcast_impl

pub fn downcast_impl<Msg, Meta, T>(
    b: Box<Implementation<Meta, Msg> + 'static>
) -> Result<Box<T>, Box<Implementation<Meta, Msg> + 'static>> where
    Meta: 'static,
    Msg: 'static,
    T: Implementation<Meta, Msg>, 

Attempt to downcast a boxed Implementation trait object.

Similar to Box::<Any>::downcast().