public void TestCache()
{
var storage1 = new MyCache <int, string>();
var containsBefore1 = storage1.Contains(1);
storage1.Upsert(1, "value1");
var containsAfter1 = storage1.Contains(1);
var value1 = storage1.Get(1);
var storage2 = new MyCache <int, string>();
var containsBefore2 = storage2.Contains(1);
storage2.Upsert(1, "value2");
var containsAfter2 = storage2.Contains(1);
var value2 = storage2.Get(1);
}