}

    @Override
    public void start(String context) {
        contextStack.addFirst(context);
    }

    @Override
    public void finish() {
        contextStack.removeFirst();
    }

    void projectFinished(String projectId);

    void executionFailure(String projectId, boolean halted, String exception);

    void mojoStarted(ExecutionEvent event);

    void finish(int exitCode) throws Exception;

    void fail(Throwable t) throws Exception;

    void log(String msg);

    void transfer(String projectId, TransferEvent e);

	}
	// Wait for all parallel RLock()s to succeed.
	for range numReaders {
		<-clocked
	}
	for range numReaders {
		cunlock <- true
	}
	// Wait for the goroutines to finish.
	for range numReaders {
		<-cdone
	}
}

// Borrowed from rwmutex_test.go
func TestParallelReaders(t *testing.T) {
	defer runtime.GOMAXPROCS(runtime.GOMAXPROCS(-1))
	doTestParallelReaders(1, 4)

   * into user code.
   *
   * @param enqueuedCall a call to enqueue in the synchronized block
   * @param finishedCall a call to finish in the synchronized block
   * @param finishedAsyncCall an async call to finish in the synchronized block
   */
  private fun promoteAndExecute(
    enqueuedCall: AsyncCall? = null,
    finishedCall: RealCall? = null,

        return Collections.emptyList();
    }

    @Override
    public Artifact transformArtifact(Artifact artifact) {
        return artifact;
    }

    @Override
    public Collection<? extends Metadata> finish(Collection<? extends Artifact> artifacts) {
        return snapshots.values();
    }

   *
   * <p>If another call to {@link #get} or {@link #getUnchecked} is currently loading the value for
   * {@code key}, simply waits for that thread to finish and returns its loaded value. Note that
   * multiple threads can concurrently load values for distinct keys.
   *
   * <p>Caches loaded by a {@link CacheLoader} will call {@link CacheLoader#load} to load new values

if [[ "$TFCI_DOCKER_PULL_ENABLE" == 1 ]]; then
  # Simple retry logic for docker-pull errors. Sleeps if a pull fails.
  # Pulling an already-pulled container image will finish instantly, so
  # repeating the command costs nothing.
  docker pull "$TFCI_DOCKER_IMAGE" || sleep 15
  docker pull "$TFCI_DOCKER_IMAGE" || sleep 30
  docker pull "$TFCI_DOCKER_IMAGE" || sleep 60

   *
   * <p>If another call to {@link #get} or {@link #getUnchecked} is currently loading the value for
   * {@code key}, simply waits for that thread to finish and returns its loaded value. Note that
   * multiple threads can concurrently load values for distinct keys.
   *
   * <p>Caches loaded by a {@link CacheLoader} will call {@link CacheLoader#load} to load new values

        infoLine('-');

        Instant finish = MonotonicClock.now();

        Duration time = Duration.between(session.getRequest().getStartInstant(), finish);

        String wallClock = session.getRequest().getDegreeOfConcurrency() > 1 ? " (Wall Clock)" : "";

        logger.info("Total time:  {}{}", formatDuration(time), wallClock);

        return Collections.emptyList();
    }

    @Override
    public Artifact transformArtifact(Artifact artifact) {
        return artifact;
    }

    @Override
    public Collection<? extends Metadata> finish(Collection<? extends Artifact> artifacts) {
        for (Artifact artifact : artifacts) {
            Object key = VersionsMetadata.getKey(artifact);
            if (processedVersions.get(key) == null) {