using System;

​

public class Message {

    public string Title {get;}

}

​

public class AccountMessage : Message {

    public new string Title {get;} = "AccountMessage";

}

​

public interface IServiceBusSender<out T> where T: Message

{

    public T SendMessage(string message);

}

​

public class ServiceBusSender<T> : IServiceBusSender<T> where T : Message, new()

{

    public T SendMessage(string message) {

        Console.WriteLine("Title: " + message);

        return new T();

    }

}

​

​

public class Program

{

    public static void Main()

    {

        {

            IServiceBusSender<AccountMessage> accountSender = new ServiceBusSender<AccountMessage>();

            accountSender.SendMessage("100% AccountMessage");

        }

        {

            IServiceBusSender<Message> accountSender = new ServiceBusSender<AccountMessage>();

            Console.WriteLine(accountSender.SendMessage("AccountMessage to Message") != null);

        }

        {

            IServiceBusSender<AccountMessage> accountSender = new ServiceBusSender<Message>();

            Console.WriteLine(accountSender.SendMessage("Message to AccountMessage") != null);

        }

    }

}