 The client uses a checksum to identify the
   * resource and an {@link ApplicationId} to identify which application will be
   * using the resource.
   * </p>
   *
   * <p>
   * The <code>SharedCacheManager</code> responds with whether or not the
   * resource exists in the cache. If the resource exists, a <code>Path</code>
   * to the resource in the shared cache is returned. If the resource does not
   * exist, the response is empty.
 The client uses a checksum to identify the
   * resource and an {@link ApplicationId} to identify which application will be
   * using the resource.
   * </p>
   *
   * <p>
   * The <code>SharedCacheManager</code> responds with whether or not the
   * resource exists in the cache. If the resource exists, a <code>Path</code>
   * to the resource in the shared cache is returned. If the resource does not
   * exist, the response is empty. | ClientSCMProtocol.java