public void TestMediator()
{
var mediator = new Mediator <string>();
var colleague1 = new Colleague <string>("Colleague 1");
var colleague2 = new Colleague <string>("Colleague 2");
var colleague3 = new Colleague <string>("Colleague 3");
mediator.Register(colleague1);
mediator.Register(colleague2);
mediator.Register(colleague3);
colleague1.SendMessage(mediator, "Test message 1");
// OUTPUT: Colleague 2 received Test message 1.
// OUTPUT: Colleague 3 received Test message 1.
}
