public ConnectionConfig build() {
            return new ConnectionConfig(
                    connectTimeout != null ? connectTimeout : DEFAULT_CONNECT_TIMEOUT,
                    socketTimeout,
                    validateAfterInactivity,
                    timeToLive);
        }
@return this instance.
@see #setTimeToLive(TimeValue)
httpclient5/src/main/java/org/apache/hc/client5/http/config/ConnectionConfig.java