Matthias Einwag Matthias247

A case for CancellationTokens

Background

The Rust async working group is currently actively discusing on ways to improve async/await. Niko Matsakis documented the main goals and ideas in the async vision document.

As part of the improved async ecosytem, users should be able to make use of

Async/Await - The challenges besides syntax - Cancellation

This is the second article in a series of articles around Rusts new async/await feature. The first article about interfaces can be found here.

In this part of the series we want to a look at a mechanism which behaves very different in Rust than in all other languages which feature async/await support. This mechanism is Cancellation.

Async/Await - The challenges besides syntax

4 years after after the release of Rust 1.0, it seems like Rust is now finally getting close to getting support for async/await - a language feature which aims to make it easier to write programs in an asynchronous fashion (where multiple logical tasks get multiplexed on a lower number of OS threads).

One of the last steps before the feature is stabilized is choosing the best possible syntax. The discussions around syntax have triggered an enormous

	Channels (Single Threaded)/intrusive local channel with producers/5
	time: [31.879 us 36.663 us 45.492 us]
	Channels (Single Threaded)/intrusive local channel with producers/20
	time: [25.602 us 25.952 us 26.363 us]
	Channels (Single Threaded)/intrusive local channel with producers/100
	time: [58.846 us 62.851 us 66.238 us]

	Channels (Single Threaded)/intrusive channel with producers/5
	time: [37.125 us 37.235 us 37.315 us]
	Channels (Single Threaded)/intrusive channel with producers/20