using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello World");

        SpecificRequestBuilder srb = new SpecificRequestBuilder();

        srb.WithExtras().WithDetails().Build();

    }

}

​

public class BigRequest { }

​

public class CommonRequestBuilder 

{

    protected readonly BigRequest _request;

​

    public CommonRequestBuilder()

    {

         _request = new BigRequest();

    }

​

    public CommonRequestBuilder WithExtras()

    {

        // add extra stuff to _request

        return this;

    }

​

    public BigRequest Build()

    {

        return _request;

    }

}

​

public class SpecificRequestBuilder : CommonRequestBuilder

{

    public SpecificRequestBuilder WithDetails()

    {

        // add some stuff to _request

        return this;

    }

​

​

    public new SpecificRequestBuilder WithExtras()

    {

        return (SpecificRequestBuilder)base.WithExtras();

    }

}