* only contain entries which are already present in the cache.
   *
   * @since 11.0
   */
  /*
   * <? extends Object> is mostly the same as <?> to plain Java. But to nullness checkers, they
   * differ: <? extends Object> means "non-null types," while <?> means "all types."
   */
  ImmutableMap<K, V> getAllPresent(Iterable<? extends Object> keys);

  /**

        String getName();

        /**
         * Returns the file extension to be used for given checksum file (without leading dot), never {@code null}. The
         * extension should be file and URL path friendly, and may differ from algorithm name.
         * The checksum extension SHOULD NOT contain dot (".") character.
         * Example: "sha1".
         */
        @Nonnull
        String getFileExtension();

        /**

   * only contain entries which are already present in the cache.
   *
   * @since 11.0
   */
  /*
   * <? extends Object> is mostly the same as <?> to plain Java. But to nullness checkers, they
   * differ: <? extends Object> means "non-null types," while <?> means "all types."
   */
  ImmutableMap<K, V> getAllPresent(Iterable<? extends Object> keys);

  /**