pub trait BalancingStrategy<K: Send> {
fn add<'life0, 'async_trait>(
&'life0 self,
_k: K,
_n: usize
) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>
where
'life0: 'async_trait,
Self: 'async_trait;
fn remove<'life0, 'async_trait>(
&'life0 self,
_k: K
) -> Pin<Box<dyn Future<Output = ()> + Send + 'async_trait>>
where
'life0: 'async_trait,
Self: 'async_trait;
fn select<'life0, 'async_trait>(
&'life0 self
) -> Pin<Box<dyn Future<Output = Option<K>> + Send + 'async_trait>>
where
'life0: 'async_trait,
Self: 'async_trait;
}