Invokable

If handler executes an action, but doesn't return any value, then Avalanche.Void can used as return type.

/// <summary>Request to alarm</summary>
public record struct AlarmRequest : IRequestInvocation { }
/// <summary>Handle alarm request</summary>
public class AlarmHandler : IHandler<AlarmRequest, Avalanche.Void>
{
    public void Handle(IQuery<AlarmRequest, Avalanche.Void> query)
    {
        // Alarm system
        Console.WriteLine("ALARM!!!!");
        // Assign void to indicate that request is handled
        query.Response.SetValueVoid();
    }
}

Service can be called with .Invoke() and .InvokeAsync() if return value is not needed.

// Create service
IService service = Services.Create(new AlarmHandler());
// Create request
AlarmRequest alarmRequest = new AlarmRequest();
// Issue alarm
service.TryInvoke(alarmRequest);