ZeroAlloc.AsyncEvents 1.0.0

.NET 8.0 This package targets .NET 8.0. The package is compatible with this framework or higher. .NET Standard 2.0 This package targets .NET Standard 2.0. The package is compatible with this framework or higher. 
dotnet add package ZeroAlloc.AsyncEvents --version 1.0.0
                    


                    

                
NuGet\Install-Package ZeroAlloc.AsyncEvents -Version 1.0.0
This command is intended to be used within the Package Manager Console in Visual Studio, as it uses the NuGet module's version of Install-Package. 
<PackageReference Include="ZeroAlloc.AsyncEvents" Version="1.0.0" />
For projects that support PackageReference, copy this XML node into the project file to reference the package. 
<PackageVersion Include="ZeroAlloc.AsyncEvents" Version="1.0.0" />
                    


                            Directory.Packages.props
                        

                    

                
<PackageReference Include="ZeroAlloc.AsyncEvents" />
                    


                            Project file
For projects that support Central Package Management (CPM), copy this XML node into the solution Directory.Packages.props file to version the package. 
paket add ZeroAlloc.AsyncEvents --version 1.0.0
                    


                    

                
#r "nuget: ZeroAlloc.AsyncEvents, 1.0.0"
#r directive can be used in F# Interactive and Polyglot Notebooks. Copy this into the interactive tool or source code of the script to reference the package. 
#:package ZeroAlloc.AsyncEvents@1.0.0
#:package directive can be used in C# file-based apps starting in .NET 10 preview 4. Copy this into a .cs file before any lines of code to reference the package. 
#addin nuget:?package=ZeroAlloc.AsyncEvents&version=1.0.0
                    


                            Install as a Cake Addin
                        

                    

                
#tool nuget:?package=ZeroAlloc.AsyncEvents&version=1.0.0
                    


                            Install as a Cake Tool

ZeroAlloc.AsyncEvents

Zero-allocation async event handler structs for .NET. Lock-free registration, ValueTask invocation, ArrayPool parallel dispatch.

Key Characteristics

  • Lock-free registration — CAS-loop register/unregister, no locks
  • ValueTask throughout — no Task allocations on hot paths
  • ArrayPool parallel dispatch — rented array for fan-out, returned immediately after WhenAll
  • Multi-target — netstandard2.0, netstandard2.1, net8.0, net10.0
  • AOT compatible

Performance

10 handlers registered, invoked once. Compared against EventHandler<T> (sync multicast, baseline) and naive async (Func<string, Task> + Task.WhenAll). BenchmarkDotNet v0.14.0, .NET 9, X64 RyuJIT AVX2.

Method Mean Error StdDev Ratio Allocated
Sync_MulticastDelegate_10Handlers 22.96 ns 0.926 ns 2.597 ns 1.01 —
NaiveAsync_TaskWhenAll_10Handlers 203.48 ns 4.111 ns 7.307 ns 8.96x 280 B
ZeroAlloc_Parallel_10Handlers 70.10 ns 1.446 ns 4.103 ns 3.09x 136 B
ZeroAlloc_Sequential_10Handlers 16.10 ns 0.655 ns 1.857 ns 0.71x —

ZeroAlloc sequential mode is 30% faster than a sync multicast delegate with zero allocations. ZeroAlloc parallel mode is 3× faster than naive async with 51% less memory.

Installation

dotnet add package ZeroAlloc.AsyncEvents

Quick Start

// Declare
private AsyncEventHandler<OrderPlacedArgs> _orderPlaced = new(InvokeMode.Parallel);

// Expose as a C# event with explicit add/remove
public event AsyncEvent<OrderPlacedArgs> OrderPlaced
{
    add    => _orderPlaced.Register(value);
    remove => _orderPlaced.Unregister(value);
}

// Invoke
await _orderPlaced.InvokeAsync(new OrderPlacedArgs(orderId), cancellationToken);

Async INotify* Interfaces

Async INotify* interfaces and event args are provided by ZeroAlloc.Notify, which builds on this package.

Design Philosophy

AsyncEventHandler<TArgs> is a struct wrapping a State reference — copy semantics are intentional and match how event fields work in C#. Use it as a private field and expose Register/Unregister methods, or use the +=/-= operators directly.

CancellationToken is threaded through every call site — handlers opt into cooperative cancellation at the delegate boundary. Sequential mode respects cancellation between handler invocations; parallel mode checks before dispatch.

See docs/ for full documentation.

Product Compatible and additional computed target framework versions.
.NET net5.0 was computed.  net5.0-windows was computed.  net6.0 was computed.  net6.0-android was computed.  net6.0-ios was computed.  net6.0-maccatalyst was computed.  net6.0-macos was computed.  net6.0-tvos was computed.  net6.0-windows was computed.  net7.0 was computed.  net7.0-android was computed.  net7.0-ios was computed.  net7.0-maccatalyst was computed.  net7.0-macos was computed.  net7.0-tvos was computed.  net7.0-windows was computed.  net8.0 is compatible.  net8.0-android was computed.  net8.0-browser was computed.  net8.0-ios was computed.  net8.0-maccatalyst was computed.  net8.0-macos was computed.  net8.0-tvos was computed.  net8.0-windows was computed.  net9.0 was computed.  net9.0-android was computed.  net9.0-browser was computed.  net9.0-ios was computed.  net9.0-maccatalyst was computed.  net9.0-macos was computed.  net9.0-tvos was computed.  net9.0-windows was computed.  net10.0 is compatible.  net10.0-android was computed.  net10.0-browser was computed.  net10.0-ios was computed.  net10.0-maccatalyst was computed.  net10.0-macos was computed.  net10.0-tvos was computed.  net10.0-windows was computed. 
.NET Core netcoreapp2.0 was computed.  netcoreapp2.1 was computed.  netcoreapp2.2 was computed.  netcoreapp3.0 was computed.  netcoreapp3.1 was computed. 
.NET Standard netstandard2.0 is compatible.  netstandard2.1 is compatible. 
.NET Framework net461 was computed.  net462 was computed.  net463 was computed.  net47 was computed.  net471 was computed.  net472 was computed.  net48 was computed.  net481 was computed. 
MonoAndroid monoandroid was computed. 
MonoMac monomac was computed. 
MonoTouch monotouch was computed. 
Tizen tizen40 was computed.  tizen60 was computed. 
Xamarin.iOS xamarinios was computed. 
Xamarin.Mac xamarinmac was computed. 
Xamarin.TVOS xamarintvos was computed. 
Xamarin.WatchOS xamarinwatchos was computed. 
Compatible target framework(s)
Included target framework(s) (in package)
Learn more about Target Frameworks and .NET Standard.

NuGet packages (2)

Showing the top 2 NuGet packages that depend on ZeroAlloc.AsyncEvents:

Package Downloads
AdoNet.Async.DataSet

Async DataSet and DataTable for ADO.NET (System.Data). Includes AsyncDataTable, AsyncDataSet, and AsyncDataAdapter.
ZeroAlloc.Notify

Source-generated async INotifyPropertyChanged, INotifyPropertyChanging, INotifyCollectionChanged and INotifyDataErrorInfo for .NET. Zero-allocation, ValueTask-based, no fire-and-forget.

GitHub repositories

This package is not used by any popular GitHub repositories.

Version Downloads Last Updated
1.0.0 53 3/27/2026
0.2.1 24 3/27/2026