IDistributedCache methods swallowing exceptions

[dengber]

For IDistributedCache methods of MemcachedClient class, when operation failed, they return default values.
They should throw exceptions so that the invoker can know operation failed or not.

[cnblogs-dudu]

Add SuppressException option in EnyimMemcachedCore 2.5.6 to disable swallowing.

{
  "enyimMemcached": {
    "suppressException": "false"
  }
}

[dengber]

Thank you for your quickly response!