Function futures::executor::with_notify

pub fn with_notify<F, T, R>(notify: &T, id: usize, f: F) -> R where
    F: FnOnce() -> R,
    T: Clone + Into<NotifyHandle>, 

Sets the NotifyHandle of the current task for the duration of the provided closure.

This function takes a type that can be converted into a notify handle, notify and id, and a closure f. The closure f will be executed such that calls to task::current() will store a reference to the notify handle provided, not the one previously in the environment.

Note that calls to task::current() in the closure provided will not be equivalent to task::current() before this method is called. The two tasks returned will notify different handles, and the task handles pulled out during the duration of this closure will not notify the previous task. It’s recommended that you call task::current() in some capacity before calling this function to ensure that calls to task::current() inside of this closure can transitively wake up the outer task.

Panics

This function will panic if it is called outside the context of a future’s task. This is only valid to call once you’ve already entered a future via Spawn::poll_* functions.