pub trait TokenProvider<'a> {
type T;
fn token<'life0, 'life1, 'async_trait>(
&'life0 mut self,
identity: &'life1 Identity<'a>
) -> Pin<Box<dyn Future<Output = Result<Self::T>> + Send + 'async_trait>>
where
'a: 'async_trait,
'life0: 'async_trait,
'life1: 'async_trait,
Self: 'async_trait;
}