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Fire-and-Forget Calls with RpcNoWait ​

Sometimes you need to send a message to the server without waiting for a response. Common use cases include:

  • Sending analytics events
  • Ping/heartbeat messages
  • Push notifications from server to client (reverse RPC)
  • Any scenario where you don't need confirmation

RpcNoWait is a special return type that tells ActualLab.Rpc to fire the call without waiting for the response.

Defining RpcNoWait Methods ​

Use Task<RpcNoWait> as the return type for fire-and-forget methods:

cs
public interface ISimpleService : IRpcService
{
    // Fire-and-forget method - caller won't wait for completion
    Task<RpcNoWait> Ping(string message);
}

Implementing RpcNoWait Methods ​

The server-side implementation should return default (or RpcNoWait.Tasks.Completed for synchronous completion):

cs
public class SimpleService : ISimpleService
{
    public async Task<RpcNoWait> Ping(string message)
    {
        // Process the message (e.g., log it, update state, etc.)
        Console.WriteLine($"Received ping: {message}");

        // Return default - the caller won't wait for this anyway
        return default;
    }
}

Calling RpcNoWait Methods ​

From the client side, you can await the call or ignore the result:

cs
// You can await it - completes immediately after sending
await simpleService.Ping("Hello!");

// Or fire-and-forget (but be aware of potential connection issues)
_ = simpleService.Ping("Hello!");

Important

RpcNoWait calls are dropped if there is no active connection. They are not queued or retried. To maximize delivery likelihood, wait for the connection to be established first:

cs
var peer = services.RpcHub().GetClientPeer(RpcPeerRef.Default);
await peer.WhenConnected(cancellationToken);
await simpleService.Ping("Now it's very likely to be sent!");

Server-to-Client Calls ​

RpcNoWait is commonly used for server-to-client (reverse RPC) calls. See Server-to-Client Calls for details.