pub trait MapExtra<Extra: 'static + Clone = ()> {
type Mapped: 'static + Clone;
// Required method
fn map_extra(&self, extra: Extra) -> Self::Mapped;
}pub trait MapExtra<Extra: 'static + Clone = ()> {
type Mapped: 'static + Clone;
// Required method
fn map_extra(&self, extra: Extra) -> Self::Mapped;
}