pub fn map_async<'a, Projection, Input, Output, NewType, Args, Descr>(
proj: Projection
) -> Handler<'a, Input, Output, Descr> where
Input: Clone,
Projection: Injectable<Input, NewType, Args> + Send + Sync + 'a,
Input: Insert<NewType> + Send + 'a,
Output: 'a,
Descr: HandlerDescription,
NewType: Send, Expand description
The asynchronous version of map.