+allowed, so duplication is not checked. Executing this function with the
+C<MEMCACHED_BEHAVIOR_USE_UDP> behavior set will result in a
+C<MEMCACHED_INVALID_HOST_PROTOCOL>.
+
+memcached_server_add_udp() pushes a single UDP server into the C<memcached_st>
+structure. This server will be placed at the end. Duplicate servers are
+allowed, so duplication is not checked. Executing this function with out
+setting the C<MEMCACHED_BEHAVIOR_USE_UDP> behavior will result in a
+C<MEMCACHED_INVALID_HOST_PROTOCOL>.