<version>1.6.0</version>
     </dependency>
     ```

 *  New: `Cache.initialize()`. Call this on a background thread to eagerly
    initialize the response cache.
 *  New: Fold `MockWebServerRule` into `MockWebServer`. This makes it easier to
    write JUnit tests with `MockWebServer`. The `MockWebServer` library now
    depends on JUnit, though it continues to work with all testing frameworks.