public static IChangeToken CreateChangeTokenForKey(string key)
 {
     if (string.IsNullOrEmpty(key))
     {
         throw new ArgumentNullException(nameof(key));
     }
     return(new CompositeChangeToken(new[] { CreateChangeToken(), CacheCancellableTokensRegistry.CreateChangeToken(GenerateRegionTokenKey(key)) }));
 }
 public static IChangeToken CreateChangeToken()
 {
     return(CacheCancellableTokensRegistry.CreateChangeToken(GenerateRegionTokenKey()));
 }