#async #async-std #tokio #scoped #spawn


Spawn scoped (non 'static) asynchronous futures for async_std and tokio runtimes

12 releases

new 0.8.0 Nov 16, 2023
0.7.1 Nov 17, 2022
0.7.0 Jul 7, 2021
0.6.1 Feb 14, 2021
0.3.1 Dec 24, 2019

#94 in Asynchronous

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Enables controlled spawning of non-'static futures when using the async-std or tokio executors.


Present executors (such as async-std, tokio, etc.) all support spawning 'static futures onto a thread-pool. However, they do not support spawning futures with lifetime smaller than 'static.

While the future combinators such as for_each_concurrent offer concurrency, they are bundled as a single Task structure by the executor, and hence are not driven parallelly. This can be seen when benchmarking a reasonable number (> ~1K) of I/O futures, or a few CPU heavy futures.


The API is meant to be a minimal wrapper around efficient executors. Users may use "use-async-std", or the "use-tokio" features, to obtain a specific global executor implementation. These features provide TokioScope and AsyncScope that support spawning, and blocking. However, none of those features are necessary - you may freely implement your own executor. See docs.rs for detailed documentation.


Licensed under either of Apache License, Version 2.0 or MIT license at your option.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this crate by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.


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