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); });
}
