AwaitExtensions

AwaitExtensions – Awaitable WaitHandle Support for .NET

This lightweight library adds await support for ordinary WaitHandle objects such as ManualResetEvent, AutoResetEvent, and others.

It exposes two simple extension methods:

• GetAwaiter() — Enables await handle;
• ToTask() — Converts a WaitHandle into a Task that completes when the handle is signaled

This makes it easy to integrate traditional wait-based APIs into modern async/await workflows.

✨ Features

• Await any WaitHandle directly
• Fully compatible with async/await patterns
• Minimal, dependency-free implementation
• Available as a NuGet package

📦 Installation

Add the NuGet package to your project:

dotnet add package AwaitExtensions

Or install via the NuGet Package Manager UI.

🚀 Usage

Awaiting a WaitHandle

var evt = new ManualResetEvent(false);

// Somewhere in your async method:
await evt;   // resumes when the event is signaled

Converting to a Task

var evt = new ManualResetEvent(false);
Task t = evt.ToTask();

await t;

Example

public async Task WaitForSignalAsync()
{
    using var evt = new ManualResetEvent(false);

    _ = Task.Run(() =>
    {
        Thread.Sleep(1000);
        evt.Set();
    });

    Console.WriteLine("Waiting...");
    await evt;
    Console.WriteLine("Signal received!");
}

🔧 How It Works

The implementation internally uses:

• ThreadPool.RegisterWaitForSingleObject to react to the signal
• TaskCompletionSource<object> to complete the returned task
• A small lock to ensure safe initialization and unregistration

The result is a task that completes as soon as the handle is signaled.

🙏 Acknowledgements

The core implementation is based on a gist originally published by Andrew Arnott:
👉 https://gist.github.com/AArnott/1084951
Huge thanks to Andrew for sharing the elegant original version!

This package only wraps and redistributes the same idea for easier consumption.