@UnstableApi
    public ClientFactoryBuilder idleTimeout(Duration idleTimeout, boolean keepAliveOnPing) {
        return idleTimeoutMillis(requireNonNull(idleTimeout, "idleTimeout").toMillis(), keepAliveOnPing);
    }
Sets the idle timeout of a socket connection. The connection is closed if there is no request in
progress for the given amount of time. If {@code keepAliveOnPing} is true, the idle timeout is reset
when an HTTP/2 PING frame or the response of {@code "OPTIONS * HTTP/1.1"} is received.
core/src/main/java/com/linecorp/armeria/client/ClientFactoryBuilder.java