memcached_lib_version() is used to return a simple version string representing
the libmemcached version (version of the client library, not server)
memcached_version() is used to set the major, minor, and micro versions of each
memcached server being used by the memcached_st connection structure. It returns the
memcached server return code.
RETURN
A string with the version of libmemcached driver is returned from
memcached_lib_version()
A value of type "memcached_return_t" is returned from memcached_version()
On success that value will be "MEMCACHED_SUCCESS". If called with the
"MEMCACHED_BEHAVIOR_USE_UDP" behavior set, the value "MEMCACHED_NOT_SUPPORTED"
will be returned. Use memcached_strerror() to translate this value to
a printable string.