+memcached_server_by_key() allows you to provide a key and retrieve the
+server which would be used for assignment. This structure is cloned
+from its original structure and must be freed. If NULL is returned you
+should consult *error. The returning structure should be freed with
+memcached_server_free().
+
+memcached_server_get_last_disconnect() returns a pointer to the last server
+for which there was a connection problem. It does not mean this particular
+server is currently dead but if the library is reporting a server is,
+the returned server is a very good candidate.
+