private static void awaitBlockedOnInstanceOf(Thread t, Class<?> blocker)
      throws InterruptedException {
    while (!isThreadBlockedOnInstanceOf(t, blocker)) {
      if (t.getState() == Thread.State.TERMINATED) {
        throw new RuntimeException("Thread " + t + " exited unexpectedly");
      }
      Thread.sleep(1);
    }
  }

  private static boolean isThreadBlockedOnInstanceOf(Thread t, Class<?> blocker) {

   *
   * This method is safe to be called concurrently, but provides limited guarantees. If a transport
   * layer connection has been established (such as a HTTP/2 stream) that is terminated. Otherwise,
   * if a socket connection is being established, that is terminated.
   */
  override fun cancel() {
    if (canceled) return // Already canceled.

    canceled = true
    exchange?.cancel()
    for (plan in plansToCancel) {

    public enum Severity {
        RECOVERABLE, // Can retry the operation
        TRANSIENT, // Temporary error, retry after delay
        PERMANENT, // Operation cannot succeed
        FATAL // Connection or session must be terminated
    }

    /**
     * Error categories
     */
    public enum Category {
        AUTHENTICATION, AUTHORIZATION, NETWORK, PROTOCOL, RESOURCE, CONFIGURATION, ENCRYPTION, TIMEOUT, IO, UNKNOWN
    }

        gen.init(param);

        final byte[] derived = new byte[16];
        gen.generateBytes(derived, 0, 16);
        return derived;
    }

    /**
     * @param string
     * @return null terminated ASCII bytes
     */
    private static byte[] toCBytes(final String string) {
        final byte[] data = new byte[string.length() + 1];

         * @return true if the thread is actively executing
         */
        public boolean isRunning() {
            return running;
        }

        /**
         * Waits for the crawling thread to terminate.
         * This method blocks until the thread completes its execution.
         * Interrupted exceptions are caught and logged at debug level.
         */
        public void awaitTermination() {
            try {

        if (sneaky == null) {
          return sample;
        } else {
          /* Someone beat us to it! Trying again...
           *
           * Technically this loop not guaranteed to terminate, so theoretically (extremely
           * unlikely) this thread might starve, but even then, there is always going to be another
           * thread doing progress here.
           */
        }
      }
    }

        if (sneaky == null) {
          return sample;
        } else {
          /* Someone beat us to it! Trying again...
           *
           * Technically this loop not guaranteed to terminate, so theoretically (extremely
           * unlikely) this thread might starve, but even then, there is always going to be another
           * thread doing progress here.
           */
        }
      }
    }

            }
            if (exitValue != 0) {
                final StringBuilder out = new StringBuilder();
                if (processTimeout) {
                    out.append("Process is terminated due to ").append(timeout).append(" second exceeded.\n");
                }
                out.append("Exit Code: ").append(exitValue).append("\nOutput:\n").append(it.getOutput());

except as expressly provided under this License. Any attempt otherwise
to copy, modify, sublicense or distribute the Program is void, and will
automatically terminate your rights under this License. However, parties
who have received copies, or rights, from you under this License will
not have their licenses terminated so long as such parties remain in
full compliance.

5. You are not required to accept this License, since you have not

                logger.info("ThumbnailGenerator is stopped.");
            }
            exitCode = Constants.EXIT_FAIL;
        } catch (final Throwable t) {
            logger.error("ThumbnailGenerator terminated unexpectedly.", t);
            exitCode = Constants.EXIT_FAIL;
        } finally {
            if (systemMonitorTask != null) {
                systemMonitorTask.cancel();
            }