ProtoPromise

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Robust and efficient library for management of asynchronous operations.

• Allocation-free async operations
• Cancelable operations with custom allocation-free CancelationToken/Source
• Allocation-free async iterators with async Linq
• Progress with enforced normalization
• Structured concurrency
• async/await support and .Then API
• Thread safe
• Easily switch to foreground or background context
• Circular await detection
• Full causality traces
• Interoperable with Tasks and Unity's Coroutines/Awaitables
• CLS compliant

ProtoPromise conforms to the Promises/A+ Spec as far as is possible with C# (using static typing instead of dynamic), and further extends it to support Cancelations and Progress.

This library was built to work in all C#/.Net ecosystems, including Unity, Mono, .Net Framework, .Net Core, and AOT compilation. It is CLS compliant, so it is not restricted to only C#, and will work with any .Net language.

• ProtoPromise v3 supports .Net Standard 2.0 or newer (Unity 2018.3 or newer).
• ProtoPromise v2 supports .Net 3.5 or newer (Unity 5.5 or newer).

See Guides for information on how to install and use this library.
See ChangeLog for the history of changes.

Benchmarks

Compare performance to other async libraries:

| Type | Pending | Mean | Allocated | Survived | |------------- |-------- |----------:|----------:|---------:| | ProtoPromise | False | 37.56 ns | - | - | | Task | False | 49.97 ns | 192 B | - | | UniTask | False | 81.06 ns | - | - | | UnityFxAsync | False | 62.05 ns | 360 B | - | | ValueTask | False | 70.66 ns | - | - | | | | | | | | ProtoPromise | True | 401.37 ns | - | 624 B | | Task | True | 455.15 ns | 1120 B | - | | UniTask | True | 478.92 ns | - | 744 B | | UnityFxAsync | True | 433.54 ns | 1952 B | - | | ValueTask | True | 498.24 ns | 968 B | 40 B |

See the C# Asynchronous Benchmarks Repo for a full performance comparison.

Acknowledgements

This library was inspired by ES6 Promises, RSG Promises, uPromise, TPL, UniTask, AsyncEx, and UnityAsync.