public GracefulShutdownBuilder quietPeriodMillis(long quietPeriodMillis) {
        return quietPeriod(Duration.ofMillis(quietPeriodMillis));
    }
Sets the quiet period millis to wait for active requests to go end before shutting down.
0 means the server will stop right away without waiting.

<p>The default is 0.
core/src/main/java/com/linecorp/armeria/server/GracefulShutdownBuilder.java