requests.clear();

        PluginPrefixResult result = processResults(request, trace, results, requests);

        if (result != null) {
            return result;
        }

        // second try, refetch all (possibly outdated) metadata that wasn't updated in the first attempt

    @Override
    public ArtifactResolverResult resolve(ArtifactResolverRequest request)
            throws ArtifactResolverException, IllegalArgumentException {
        nonNull(request, "request");
        InternalSession session = InternalSession.from(request.getSession());
        try {
            Map<Artifact, Path> paths = new HashMap<>();

                request.getGroupId(),
                request.getArtifactId(),
                "maven-metadata.xml",
                DefaultMetadata.Nature.RELEASE_OR_SNAPSHOT);

        List<MetadataRequest> requests = new ArrayList<>();

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

        for (RemoteRepository repository : request.getRepositories()) {

            throws ArtifactResolutionException {
        List<ArtifactResult> results = new ArrayList<>();

        for (ArtifactRequest request : requests) {
            ArtifactResult result = new ArtifactResult(request);
            results.add(result);

            Artifact artifact = request.getArtifact();

  /** The HTTP {@code Access-Control-Request-Headers} header field name. */
  public static final String ACCESS_CONTROL_REQUEST_HEADERS = "Access-Control-Request-Headers";
  /** The HTTP {@code Access-Control-Request-Method} header field name. */
  public static final String ACCESS_CONTROL_REQUEST_METHOD = "Access-Control-Request-Method";
  /** The HTTP {@code Authorization} header field name. */

    public V load(K key) {
      return constant;
    }
  }

  /**
   * Returns a {@code new Object()} for every request, and increments a counter for every request.
   * An {@code Integer} loader that returns the key for {@code load} requests, and increments the
   * old value on {@code reload} requests. The load counts are accessible via {@link #getLoadCount}
   * and {@link #getReloadCount}.
   */

    protected abstract void makeKey( Request request ) throws IOException;
    protected abstract Request peekKey() throws IOException;
    protected abstract void doSend( Request request ) throws IOException;
    protected abstract void doRecv( Response response ) throws IOException;
    protected abstract void doSkip() throws IOException;

    public synchronized void sendrecv( Request request,
                    Response response,

  }

  /**
   * Returns the ratio of cache requests which were misses. This is defined as {@code missCount /
   * requestCount}, or {@code 0.0} when {@code requestCount == 0}. Note that {@code hitRate +
   * missRate =~ 1.0}. Cache misses include all requests which weren't cache hits, including
   * requests which resulted in either successful or failed loading attempts, and requests which

  }

  /**
   * Returns the ratio of cache requests which were misses. This is defined as {@code missCount /
   * requestCount}, or {@code 0.0} when {@code requestCount == 0}. Note that {@code hitRate +
   * missRate =~ 1.0}. Cache misses include all requests which weren't cache hits, including
   * requests which resulted in either successful or failed loading attempts, and requests which

   * to stop requests. You could poll for lifecycle changes in a work loop:
   *
   * <pre>
   *   public void run() {
   *     while ({@link #isRunning()}) {
   *       // perform a unit of work
   *     }
   *   }
   * </pre>
   *
   * <p>...or you could respond to stop requests by implementing {@link #triggerShutdown()}, which