* seconds:
 *
 * ```java
 * Request request = new Request.Builder()
 *     .cacheControl(new CacheControl.Builder()
 *         .maxStale(365, TimeUnit.DAYS)
 *         .build())
 *     .url("http://publicobject.com/helloworld.txt")
 *     .build();
 * ```
 *
 * The [CacheControl] class can configure request caching directives and parse response caching

    //      last modified: 105 days ago
    //             served:   5 days ago
    //   default lifetime: (105 - 5) / 10 = 10 days
    //            expires:  10 days from served date = 5 days from now
    server.enqueue(
      MockResponse.Builder()
        .addHeader("Last-Modified: " + formatDate(-105, TimeUnit.DAYS))
        .addHeader("Date: " + formatDate(-5, TimeUnit.DAYS))
        .body("A")
        .build(),