static CustomBehavior() { Null = new CustomBehavior(); Null.OnActivate(() => Task.CompletedTask); Null.OnDeactivate(() => Task.CompletedTask); Null.OnReceive((actor, message) => actor.Dispatch(message)); Null.OnReminder((actor, id) => { throw new NotImplementedException( $"Override {nameof(Actor.OnReminder)}(string id) method in " + $"class {actor.GetType()} to implement corresponding behavior"); }); const string warn = "Initial behavior has not been set"; Null.OnBecome(() => { throw new InvalidOperationException(warn); }); }