+=item MEMCACHED_BEHAVIOR_VERIFY_KEY
+
+Enabling this will cause libmemcached(3) to test all keys to verify that they
+are valid keys.
+
+=item MEMCACHED_BEHAVIOR_SORT_HOSTS
+
+Enabling this will cause hosts that are added to be placed in the host list in
+sorted order. This will defeat consisten hashing.
+
+=item MEMCACHED_BEHAVIOR_CONNECT_TIMEOUT
+
+In non-blocking mode this changes the value of the timeout during socket
+connection.
+
+=item MEMCACHED_BEHAVIOR_BINARY_PROTOCOL
+
+Enable the use of the binary protocol. Please note that you cannot toggle
+this flag on an open connection.
+
+=item MEMCACHED_BEHAVIOR_SERVER_FAILURE_LIMIT
+
+Set this value to enable the server be removed after continuous MEMCACHED_BEHAVIOR_SERVER_FAILURE_LIMIT
+times connection failure.
+
+=item MEMCACHED_BEHAVIOR_IO_MSG_WATERMARK
+
+Set this value to tune the number of messages that may be sent before
+libmemcached should start to automatically drain the input queue. Setting
+this value to high, may cause libmemcached to deadlock (trying to send data,
+but the send will block because the input buffer in the kernel is full).
+
+=item MEMCACHED_BEHAVIOR_IO_BYTES_WATERMARK
+
+Set this value to tune the number of bytes that may be sent before
+libmemcached should start to automatically drain the input queue (need
+at least 10 IO requests sent without reading the input buffer). Setting
+this value to high, may cause libmemcached to deadlock (trying to send
+data, but the send will block because the input buffer in the kernel is full).
+