code: public CompletableFuture<StreamCut> fetchHeadStreamCut(final Stream stream) {
          //Fetch segments pointing to the current HEAD of the stream.
          return controller.getSegmentsAtTime(new StreamImpl(stream.getScope(), stream.getStreamName()), 0L)
                           .thenApply( s -> new StreamCutImpl(stream, s));
      }
docs: Obtain the {@link StreamCut} pointing to the current HEAD of the Stream.
  @param stream The Stream.
  @return {@link StreamCut} pointing to the HEAD of the Stream.