scope() should be async

[thomas001]

When scope() returns all remaining scoped futures have to complete. From reading the code this is achieved via synchronous blocking and tokio::task::block_in_place. The latter only works on a corresponding multi threaded runtime.

Please evaluate whether it wouldn't be simpler to declare scope() itself async and run the future completion step asynchronously.

[jaboatman]

Such an implementation is unsafe as you can drop the scope (and borrowed data) before the spawned futures complete.

If you want that, consider using async_scoped instead. In general, consider using instead of this crate.