* the iterator is created, in any way except through the iterator's own remove method, the
   * iterator will generally throw a {@link ConcurrentModificationException}. Thus, in the face of
   * concurrent modification, the iterator fails quickly and cleanly, rather than risking arbitrary,
   * non-deterministic behavior at an undetermined time in the future.
   *

        //
        // Note that there is a race condition here which can result in missing
        // a cyclic edge: it's possible for two threads to simultaneous find
        // "safe" edges which together form a cycle. Preventing this race
        // condition efficiently without _introducing_ deadlock is probably
        // tricky. For now, just accept the race condition---missing a warning

            requests.add(new MetadataRequest(metadata, null, REPOSITORY_CONTEXT).setTrace(trace));

            for (RemoteRepository repository : request.getRepositories()) {
                requests.add(new MetadataRequest(metadata, repository, REPOSITORY_CONTEXT).setTrace(trace));
            }
        }

        // initial try, use locally cached metadata

        for ( Entry<String, Map<String, CacheEntry<DfsReferralDataInternal>>> entry : domains.entrySet() ) {
            log.trace("Domain " + entry.getKey());
            for ( Entry<String, CacheEntry<DfsReferralDataInternal>> entry2 : entry.getValue().entrySet() ) {
                log.trace("  Root " + entry2.getKey());
                if ( entry2.getValue().map != null ) {

            RequestTrace trace,
            RepositorySystem resolver,
            RemoteRepositoryManager remoteRepositoryManager,
            List<RemoteRepository> repositories,
            ProjectBuildingRequest.RepositoryMerging repositoryMerging,
            ReactorModelPool modelPool,
            Map<String, Object> parentCache) {
        this.session = session;
        this.trace = trace;
        this.resolver = resolver;

        msgs.add("* An aggregator Mojo is already executing in parallel build,    *");
        msgs.add("* but aggregator Mojos require exclusive access to reactor to   *");
        msgs.add("* prevent race conditions. This mojo execution will be blocked  *");
        msgs.add("* until the aggregator work is done.                            *");
        msgs.add("*****************************************************************");

    return stringWriter.toString();
  }

  /**
   * Returns the stack trace of {@code throwable}, possibly providing slower iteration over the full
   * trace but faster iteration over parts of the trace. Here, "slower" and "faster" are defined in
   * comparison to the normal way to access the stack trace, {@link Throwable#getStackTrace()

    return stringWriter.toString();
  }

  /**
   * Returns the stack trace of {@code throwable}, possibly providing slower iteration over the full
   * trace but faster iteration over parts of the trace. Here, "slower" and "faster" are defined in
   * comparison to the normal way to access the stack trace, {@link Throwable#getStackTrace()

  @Override
  public boolean offer(E e, long timeout, TimeUnit unit) throws InterruptedException {
    return delegate().offer(e, timeout, unit);
  }

  @Override
  public E take() throws InterruptedException {
    return delegate().take();
  }

  @Override
  @CheckForNull
  public E poll(long timeout, TimeUnit unit) throws InterruptedException {
    return delegate().poll(timeout, unit);
  }

        if (finishImmediately) {
            projectBuildFutureTask.run();
        }
        return projectBuildFutureTask;
    }

    public Future<ProjectSegment> take() throws InterruptedException {
        return null;
    }

    public Future<ProjectSegment> poll() {
        return null;
    }