code: public CompletableFuture<StreamCut> fetchTailStreamCut(final Stream stream) {
          return controller.getCurrentSegments(stream.getScope(), stream.getStreamName())
                           .thenApply(s -> {
                               latestDelegationToken.set(s.getDelegationToken());
                               Map<Segment, Long> pos =
                                       s.getSegments().stream().map(this::segmentToInfo)
                                        .collect(Collectors.toMap(SegmentInfo::getSegment, SegmentInfo::getWriteOffset));
                               return new StreamCutImpl(stream, pos);
                           });
      }
docs: Obtain the {@link StreamCut} pointing to the current TAIL of the Stream.
  @param stream The Stream.
  @return {@link StreamCut} pointing to the TAIL of the Stream.