public ClientCacheControlBuilder staleWhileRevalidate(@Nullable Duration staleWhileRevalidate) {
        staleWhileRevalidateSeconds = validateDuration(staleWhileRevalidate, "staleWhileRevalidate");
        return this;
    }
Enables or disables the {@code "stale-while-revalidate"} directive.

@param staleWhileRevalidate the value of the directive to enable, or {@code null} to disable.
core/src/main/java/com/linecorp/armeria/common/ClientCacheControlBuilder.java