Fixed "PooledSocket hangs when the server goes down".
Fixed "PooledSocket hangs when the server goes down".

oceanho/EnyimMemcached,couchbase/EnyimMemcached,haizhixing126/EnyimMemcached,enyim/EnyimMemcached,cnblogs/EnyimMemcachedCore,haizhixing126/EnyimMemcached,cnblogs/EnyimMemcachedCore,couchbaselabs/EnyimMemcached,oceanho/EnyimMemcached,DukeCheng/EnyimMemcachedCore,DukeCheng/EnyimMemcachedCore