public ClientFactoryBuilder idleTimeout(Duration idleTimeout) {
        return idleTimeoutMillis(requireNonNull(idleTimeout, "idleTimeout").toMillis());
    }
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. By default, HTTP/2 PING frames do not prevent connection from
closing. Use the method {@link ClientFactoryBuilder#idleTimeout(Duration, boolean)} to set whether to
prevent connection from closing 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