*
   * <ol>
   *   <li>calls {@link ExecutorService#shutdown()}, disabling acceptance of new submitted tasks.
   *   <li>awaits executor service termination for half of the specified timeout.
   *   <li>if the timeout expires, it calls {@link ExecutorService#shutdownNow()}, cancelling
   *       pending tasks and interrupting running tasks.
   *   <li>awaits executor service termination for the other half of the specified timeout.
   * </ol>
   *

                            if (!downloaded) {
                                // prevent additional checks of this artifact until it expires again
                                destination.setLastModified(System.currentTimeMillis());
                            }
                        } catch (UnsupportedOperationException e) {

	// Remove STANDARD StorageClass
	metadata = removeStandardStorageClass(metadata)
	// Clean meta etag keys 'md5Sum', 'etag', "expires", "x-amz-tagging".
	return cleanMetadataKeys(metadata, "md5Sum", "etag", "expires", xhttp.AmzObjectTagging, "last-modified", VersionPurgeStatusKey)
}

// Filter X-Amz-Storage-Class field only if it is set to STANDARD.

    /** Logger instance for this class */
    private static final Logger logger = LogManager.getLogger(PluginHelper.class);

    /**
     * Cache for storing available artifacts by type.
     * The cache expires after 5 minutes and has a maximum size of 10 entries.
     */
    protected LoadingCache<ArtifactType, Artifact[]> availableArtifacts = CacheBuilder.newBuilder()
            .maximumSize(10)

                }
              });
    }

    threadPool.shutdown();
    threadPool.awaitTermination(300, SECONDS);

    // Since we're not doing any more cache operations, and the cache only expires/evicts when doing
    // other operations, the cache and the removal queue won't change from this point on.

    // Verify that each received removal notification was valid

                }
              });
    }

    threadPool.shutdown();
    threadPool.awaitTermination(300, SECONDS);

    // Since we're not doing any more cache operations, and the cache only expires/evicts when doing
    // other operations, the cache and the removal queue won't change from this point on.

    // Verify that each received removal notification was valid

            public String getResponseFieldUrlLink() {
                return "url_link";
            }

            @Override
            public String getIndexFieldExpires() {
                return "expires";
            }

            @Override
            public String getIndexFieldParentId() {
                return "parent_id";
            }

            @Override

 *       Future} is "completed" even if it is cancelled while its underlying work continues on a
 *       thread, an RPC, etc. The {@code Future} is also "completed" if it fails "early" -- for
 *       example, if the deadline expires on a {@code Future} returned from {@link
 *       Futures#withTimeout} while the {@code Future} it wraps continues its underlying work. So
 *       beware: <i>Your {@code AsyncCallable} should not complete its {@code Future} until it is

            }
        }

    }

    /*
     * Build a connection. Only one thread will ever call this method at
     * any one time. If this method throws an exception or the connect timeout
     * expires an encapsulating TransportException will be thrown from connect
     * and the transport will be in error.
     */

    /**
     * Establish the transport connection
     *

  }

  /**
   * Returns a future that delegates to another but will finish early (via a {@link
   * TimeoutException} wrapped in an {@link ExecutionException}) if the specified duration expires.
   *
   * <p>The delegate future is interrupted and cancelled if it times out.
   *
   * @param delegate The future to delegate to.
   * @param time when to time out the future