code: public static MemcachedManagerBuilder memcacheAddOn() {
          final String memcacheServers = System.getenv("MEMCACHE_SERVERS");
          return memcachedConfig()
                  .username(System.getenv("MEMCACHE_USERNAME"))
                  .password(System.getenv("MEMCACHE_PASSWORD"))
                  .url(memcacheServers == null ? DEFAULT_URL : memcacheServers);
      }
docs: Configuration based on system properties set by the memcacheAddOn