* <p>Caches loaded by a {@link CacheLoader} will issue a single request to {@link
   * CacheLoader#loadAll} for all keys which are not already present in the cache. All entries
   * returned by {@link CacheLoader#loadAll} will be stored in the cache, over-writing any
   * previously cached values. This method will throw an exception if {@link CacheLoader#loadAll}
   * returns {@code null}, returns a map containing null keys or values, or fails to return an entry

   * <p>Caches loaded by a {@link CacheLoader} will issue a single request to {@link
   * CacheLoader#loadAll} for all keys which are not already present in the cache. All entries
   * returned by {@link CacheLoader#loadAll} will be stored in the cache, over-writing any
   * previously cached values. This method will throw an exception if {@link CacheLoader#loadAll}
   * returns {@code null}, returns a map containing null keys or values, or fails to return an entry

   *       CacheBuilder#refreshAfterWrite automated refreshing}
   *   <li>{@linkplain LoadingCache#getAll bulk loading requests}, including {@linkplain
   *       CacheLoader#loadAll bulk loading implementations}
   * </ul>
   *
   * <p><b>Warning:</b> For any given key, every {@code loader} used with it should compute the same

          @Override
          public Object load(Object key) throws Exception {
            return new Object();
          }

          @Override
          public Map<Object, Object> loadAll(Iterable<?> keys) throws Exception {
            Map<Object, Object> result = new HashMap<>();
            for (Object key : keys) {
              Object value = new Object();
              result.put(key, value);

          @Override
          public Object load(Object key) throws Exception {
            return new Object();
          }

          @Override
          public Map<Object, Object> loadAll(Iterable<?> keys) throws Exception {
            Map<Object, Object> result = new HashMap<>();
            for (Object key : keys) {
              Object value = new Object();
              result.put(key, value);

    }
  }

  /**
   * Returns the result of calling {@link CacheLoader#loadAll}, or null if {@code loader} doesn't
   * implement {@code loadAll}.
   */
  @Nullable Map<K, V> loadAll(Set<? extends K> keys, CacheLoader<? super K, V> loader)
      throws ExecutionException {
    checkNotNull(loader);
    checkNotNull(keys);
    Stopwatch stopwatch = Stopwatch.createStarted();
    Map<K, V> result;

    }
  }

  /**
   * Returns the result of calling {@link CacheLoader#loadAll}, or null if {@code loader} doesn't
   * implement {@code loadAll}.
   */
  @Nullable Map<K, V> loadAll(Set<? extends K> keys, CacheLoader<? super K, V> loader)
      throws ExecutionException {
    checkNotNull(loader);
    checkNotNull(keys);
    Stopwatch stopwatch = Stopwatch.createStarted();
    Map<K, V> result;