class Client void Main Subject subject new Proxy subject Request abstr

class Client
{
    void Main()
    {
        Subject subject = new Proxy();
        subject.Request();
    }
}
abstract class Subject
{
    public abstract void Request();
}
 
class RealSubject : Subject
{
    public override void Request()
    {}
}
class Proxy : Subject
{
    RealSubject realSubject;
    public override void Request()
    {
        if (realSubject == null)
            realSubject = new RealSubject();
        realSubject.Request();
    }
}