test.cs

#region AutoGenerated
public class DataQHello
{
	public int A { get; set; }
}

public class DataRHello
{
	public int A { get; set; }
}

public abstract class BaseResponseHello
{
	public abstract void RHello(int a);

	public void RHello(DataRHello data)
	{
		RHello(data.A);
	}
}

public static void QHello(int A, BaseResponseHello callback)
{
	QHello(new DataQHello { A = A }, callback);
}
#endregion AutoGenerated

#region HandleLibrary
private static void QHello(DataQHello hello, BaseResponseHello callback)
{
	// TODO request handler
	callback.RHello(new DataRHello { A = 20 });
}
#endregion HandleLibrary

public class Example : BaseResponseHello
{
	public void Start()
	{
		Program.QHello(A: 10, callback: this);
	}

	public override void RHello(int a)
	{
		Console.WriteLine(a);
	}
}