code: public CompletableFuture<List<V>> loadMany(List<K> keys) {
          return loadMany(keys, Collections.emptyList());
      }
docs: Requests to load the list of data provided by the specified keys asynchronously, and returns a composite future
  of the resulting values.
  <p>
  If batching is enabled (the default), you'll have to call {@link DataLoader#dispatch()} at a later stage to
  start batch execution. If you forget this call the future will never be completed (unless already completed,
  and returned from cache).
  
  @param keys the list of keys to load
  
  @return the composite future of the list of values