updater.start();
    }

    @Override
    public void close() {
        if (closed.compareAndSet(false, true)) {
            updater.interrupt();
        }
    }

    public TransferListener getDelegate() {
        return delegate;
    }

    private void feedConsumer() {
        final ArrayList<Exchange> batch = new ArrayList<>(batchMaxSize);
        try {
            while (true) {

        this.eventQueue = new ArrayBlockingQueue<>(queueSize);
        Thread updater = new Thread(this::feedConsumer);
        updater.setDaemon(true);
        updater.start();
    }

    public TransferListener getDelegate() {
        return delegate;
    }

    private void feedConsumer() {
        final ArrayList<Exchange> batch = new ArrayList<>(batchMaxSize);
        try {
            while (true) {

                        .build();
                execs.add(execution);

                if (mojo.getDependencies() != null) {
                    mojo.getDependencies().forEach(d -> deps.add(d.getDelegate()));
                }

                Plugin plugin = Plugin.newBuilder()
                        .groupId(groupId)
                        .artifactId(artifactId)
                        .version(version)

    stream.defaultReadObject();
    keyTypeOrObjectUnderJ2cl = (Class<K>) requireNonNull(stream.readObject());
    valueTypeOrObjectUnderJ2cl = (Class<V>) requireNonNull(stream.readObject());
    setDelegates(
        new EnumMap<>(keyTypeOrObjectUnderJ2cl), new EnumMap<>(valueTypeOrObjectUnderJ2cl));
    Serialization.populateMap(this, stream);
  }

            deferDeleteFile(consumer);

            project.addAttachedArtifact(createConsumerPomArtifact(project, consumer, session));
        } else if (project.getModel().getDelegate().isRoot()) {
            throw new IllegalStateException(
                    "The use of the root attribute on the model requires the buildconsumer feature to be active");
        }
    }

        MavenProject p2 = results.get(1).getProject();
        MavenProject parent = p1.getArtifactId().equals("parent") ? p1 : p2;
        assertEquals(List.of("child"), parent.getModel().getDelegate().getSubprojects());
    }

    @Test
    public void testEmptySubprojectsElementPreventsDiscovery() throws Exception {
        File pom = getTestFile("src/test/resources/projects/subprojects-empty/pom.xml");

                plugin.setArtifactId(extension.getArtifactId());
                plugin.setVersion(extension.getVersion());
                XmlNode configuration = extension.getDelegate().getConfiguration();
                if (configuration != null) {
                    plugin.setConfiguration(new Xpp3Dom(configuration));
                }
                extensionPlugins.add(plugin);
            }

            try (OutputStream output = Files.newOutputStream(metadataFile.toPath())) {
                MetadataStaxWriter mappingWriter = new MetadataStaxWriter();
                mappingWriter.write(output, metadata.getDelegate());
            }
        } else {
            metadataFile.setLastModified(System.currentTimeMillis());
        }
    }

    @Override
    public String toString() {

     * the number of entries in the map, as that makes it easy for hostile inputs to trigger lots of
     * allocation—not that any program should be deserializing hostile inputs to begin with!)
     */
    setDelegates(new EnumMap<>(keyTypeOrObjectUnderJ2cl), new HashMap<>());
    Serialization.populateMap(this, stream);
  }

  @GwtIncompatible @J2ktIncompatible private static final long serialVersionUID = 0;

            throws PluginResolutionException {
        InternalSession iSession = InternalSession.from(session);
        RequestTraceHelper.ResolverTrace trace = RequestTraceHelper.enter(iSession, plugin.getDelegate());

        if (pluginArtifact == null) {
            pluginArtifact = toArtifact(plugin, session);
        }

        DependencyFilter collectionFilter = new ScopeDependencyFilter("provided", "test");