public void Set_then_expire()
{
var key = Guid.NewGuid().ToString();
var value = Guid.NewGuid();
var cache = new MemoryCacheProvider("region6");
cache.Overwrite(key, value);
cache.Expire(key);
Guid value2;
var exist = cache.TryGet(key, out value2);
Assert.IsFalse(exist);
Assert.AreEqual(value2, Guid.Empty);
cache.ExpireAll();
Assert.AreEqual(cache.Count(), 0);
}