* CacheLoader#reload}.
   *
   * <p>As the default implementation of {@link CacheLoader#reload} is synchronous, it is
   * recommended that users of this method override {@link CacheLoader#reload} with an asynchronous
   * implementation; otherwise refreshes will be performed during unrelated cache read and write
   * operations.
   *

   * [host] is an IP address or is considered a public suffix by the public suffix list.
   *
   * In general this method **should not** be used to test whether a domain is valid or routable.
   * Instead, DNS is the recommended source for that information.
   *
   * | URL                           | `topPrivateDomain()` |
   * | :---------------------------- | :------------------- |
   * | `http://google.com`           | `"google.com"`       |

 *
 * <h3>Non-preconditions</h3>
 *
 * <p>It is of course possible to use the methods of this class to check for invalid conditions
 * which are <i>not the caller's fault</i>. Doing so is <b>not recommended</b> because it is
 * misleading to future readers of the code and of stack traces. See <a
 * href="https://github.com/google/guava/wiki/ConditionalFailuresExplained">Conditional failures

     * IllegalArgumentException, since the call could succeed with a different argument. Those
     * exceptions' docs suggest that either is acceptable. Google's Java Practices page recommends
     * IllegalArgumentException here, in part to keep its recommendation simple: Static methods
     * should throw IllegalStateException only when they use static state.
     *

The following versions of Docker Engine are supported - *[v1.10](https://github.com/kubernetes/kubernetes/issues/19720)*, *[v1.11](https://github.com/kubernetes/kubernetes/issues/23397)*
Although *v1.9* is still compatible, we recommend upgrading to one of the supported versions.
All prior versions of docker will not be supported.

#### ThirdPartyResource