Faster.EventBus 0.0.1

Faster.EventBus – High-Performance In-Process Command & Event Dispatcher

A faster, lower-allocation alternative to MediatR for .NET real-time workloads.

Faster.EventBus is an ultra-fast mediator/event bus for .NET.
It dispatches commands with Result<T> responses and publishes events using compiled pipeline delegates, avoiding runtime reflection and minimizing allocations.

It is ideal for high-frequency request handling, simulations, UI frameworks, real-time systems, plugin architectures, and performance-critical backends.

✨ Key Features

• ✔ Near-zero overhead runtime
• ✔ No reflection after startup
• ✔ No boxing / extremely low memory allocation
• ✔ ValueTask<T> pipelines
• ✔ Middleware-style pipeline behaviors
• ✔ Command/query request-response pattern
• ✔ Publish/subscribe events
• ✔ Fully DI-integrated via IServiceProvider
• ✔ Benchmark-proven micro-latency advantage over MediatR

📦 Installation

services.AddEventBus(options =>
{
    options.AutoRegister = true; // automatically scans assemblies for handlers
});

📌 Define a Command

public record GetUserNameCommand(int UserId) : ICommand<Result<string>>;

🛠 Create a Command Handler

public class GetUserNameCommandHandler :
    ICommandHandler<GetUserNameCommand, Result<string>>
{
    public ValueTask<Result<string>> Handle(GetUserNameCommand command, CancellationToken ct)
    {
        return ValueTask.FromResult(Result<string>.Success($"User-{command.UserId}"));
    }
}

🧩 Register Services

var services = new ServiceCollection();

services.AddEventBus(options => options.AutoRegister = true);
services.AddTransient<ICommandHandler<GetUserNameCommand, Result<string>>, GetUserNameCommandHandler>();

var provider = services.BuildServiceProvider();
var bus = provider.GetRequiredService<EventDispatcher>();

🚀 Send a Command

var result = await bus.Send(new GetUserNameCommand(42));

if (result.IsSuccess)
    Console.WriteLine(result.Value); // Output: User-42

🔧 Pipeline Behavior Example

public class LoggingBehavior : ICommandPipelineBehavior<GetUserNameCommand, Result<string>>
{
    public async ValueTask<Result<string>> Handle(
        GetUserNameCommand cmd, CancellationToken ct, CommandHandlerDelegate<Result<string>> next)
    {
        Console.WriteLine("Before");
        var result = await next();
        Console.WriteLine("After");
        return result;
    }
}

Register Behavior

services.AddSingleton<ICommandPipelineBehavior<GetUserNameCommand, Result<string>>, LoggingBehavior>();

📣 Publish / Subscribe Events

public record UserCreatedEvent(int UserId) : IEvent;

public class UserCreatedEventHandler : IEventHandler<UserCreatedEvent>
{
    public ValueTask Handle(UserCreatedEvent evt, CancellationToken ct)
    {
        Console.WriteLine($"User created: {evt.UserId}");
        return ValueTask.CompletedTask;
    }
}

Use in application

bus.SubscribeEvent<UserCreatedEvent>();
await bus.PublishEvent(new UserCreatedEvent(10));

🥇 Benchmark Results vs MediatR

BenchmarkDotNet v0.15.6 • .NET 10 • 12-Core i5-12500H • Windows 11

🔥 Key takeaway

Faster.EventBus is 1.25–1.35x faster and uses 3x less memory.

❤️ Why Use It?

🙌 Final Notes

Fast, simple, reliable.
Perfect when performance matters.