id,summary,reporter,owner,description,type,status,milestone,component,version,severity,resolution,keywords,cc
11717,Associate an Executor used to launch the continuation to a promise/packaged_task constructor.,viboes,viboes,"Currently 
we have `async` function that constructs futures associated to an `Executor`. 

The `then()` member function should use this executor to launch the continuation. See #11716.

But futures can also have other sources, as e.g. a `promise` or a `packaged_task`. 
This paper proposes the addition of `Executor` aware constructors for `promise<T>` and `packaged_task<R(Args)>`
so that the continuation on the associated future make use of this executor.

We propose to: 
* Add `promise<T>::promise<T>(Executor&)` Executor aware constructor.

* Add `packaged_task<R(Args...)>::packaged_task(Executor&)` Executor aware constructor.
",Feature Requests,assigned,To Be Determined,thread,Boost 1.58.0,Problem,,,