Function in_place_scope 

pub fn in_place_scope<'scope, OP, R>(op: OP) -> R
where
    OP: FnOnce(&Scope<'scope>) -> R,

Creates a “fork-join” scope s and invokes the closure with a reference to s. This closure can then spawn asynchronous tasks into s. Those tasks may run asynchronously with respect to the closure; they may themselves spawn additional tasks into s. When the closure returns, it will block until all tasks that have been spawned into s complete.

This is just like scope() except the closure runs on the same thread that calls in_place_scope(). Only work that it spawns runs in the thread pool.

Panics

If a panic occurs, either in the closure given to in_place_scope() or in any of the spawned jobs, that panic will be propagated and the call to in_place_scope() will panic. If multiple panics occurs, it is non-deterministic which of their panic values will propagate. Regardless, once a task is spawned using scope.spawn(), it will execute, even if the spawning task should later panic. in_place_scope() returns once all spawned jobs have completed, and any panics are propagated at that point.