@UnstableApi
    public static long defaultHttp1ConnectionCloseDelayMillis() {
        return DEFAULT_HTTP1_CONNECTION_CLOSE_DELAY_MILLIS;
    }
Returns the default time in milliseconds to wait before closing an HTTP/1 connection when a server needs
to close the connection. This allows to avoid a server socket from remaining in the TIME_WAIT state
instead of CLOSED when a connection is closed.

<p>The default value of this flag is
{@value DefaultFlagsProvider#DEFAULT_HTTP1_CONNECTION_CLOSE_DELAY_MILLIS}. Specify the
{@code -Dcom.linecorp.armeria.defaultHttp1ConnectionCloseDelayMillis=<long>} JVM option to
override the default value. {@code 0} closes the connection immediately.</p>
core/src/main/java/com/linecorp/armeria/common/Flags.java