public ClientCacheControlBuilder staleWhileRevalidateSeconds(long staleWhileRevalidateSeconds) {
        this.staleWhileRevalidateSeconds = validateSeconds(staleWhileRevalidateSeconds,
                                                           "staleWhileRevalidateSeconds");
        return this;
    }
Enables the {@code "stale-while-revalidate"} directive.

@param staleWhileRevalidateSeconds the value in seconds.
core/src/main/java/com/linecorp/armeria/common/ClientCacheControlBuilder.java