modify the Connect method in RedisNativeClient_Utils in case that the C#
Socket connection takes so long that if the destination is unreachable.
Modify the ShardedRedisClientManager that start a thread to check if the
pool is reachable.if it is not reachable,then the thread will remove all
the key in ConsistentHash.SortedMap that generated base on the pool and
the pool's weight.Then add the pool to a removed list.
also the thread will check the removed list,to see if the pool is now
reachable,if so ,add to the ConsistentHash.SortedMap.