private static void RefPMethod1()
{
var a = new RefPoint();
Console.WriteLine($"RefPMethod1 - start: x = {a.x}, y = {a.y}");
RefPMethod2(a);
Console.WriteLine($"RefPMethod1 - end: x = {a.x}, y = {a.y}");
}
private static void RefPMethod2(RefPoint a)
{
Console.WriteLine($"RefPMethod2 - start: x = {a.x}, y = {a.y}");
a.x = 1;
Console.WriteLine($"RefPMethod2 - end: x = {a.x}, y = {a.y}");
}