assertTrue(Thread.holdsLock(mutex));
    return super.add(o);
  }

  @Override
  public boolean addAll(Collection<? extends E> c) {
    assertTrue(Thread.holdsLock(mutex));
    return super.addAll(c);
  }

  @Override
  public void clear() {
    assertTrue(Thread.holdsLock(mutex));
    super.clear();
  }

  @Override
  public boolean contains(@Nullable Object o) {
    assertTrue(Thread.holdsLock(mutex));

        // Simulate concurrent failures
        Thread[] threads = new Thread[5];
        for (int i = 0; i < threads.length; i++) {
            threads[i] = new Thread(() -> failover.handleFailure(failedChannel, error));
            threads[i].start();
        }

        // Wait for all threads to complete
        for (Thread thread : threads) {
            thread.join(1000);
        }

                Arrays.fill(dataArrays[i], (byte) i);

                threads[i] = new Thread(() -> {
                    digest.sign(dataArrays[index], 0, dataArrays[index].length, request, response);
                });
            }

            for (Thread t : threads) {
                t.start();
            }
            for (Thread t : threads) {
                t.join();
            }

      }
    }
  }

  private static class Interrupter implements Runnable {
    final Thread threadToInterrupt;

    Interrupter(Thread threadToInterrupt) {
      this.threadToInterrupt = threadToInterrupt;
    }

    @Override
    public void run() {
      try {
        Thread.sleep(100);
      } catch (InterruptedException e) {
        throw new AssertionError();
      } finally {

    assertTrue(Thread.holdsLock(mutex));
    return super.add(o);
  }

  @Override
  public boolean addAll(Collection<? extends E> c) {
    assertTrue(Thread.holdsLock(mutex));
    return super.addAll(c);
  }

  @Override
  public void clear() {
    assertTrue(Thread.holdsLock(mutex));
    super.clear();
  }

  @Override
  public boolean contains(@Nullable Object o) {
    assertTrue(Thread.holdsLock(mutex));

        // Test thread safety
        Thread[] threads = new Thread[10];
        for (int i = 0; i < threads.length; i++) {
            threads[i] = new Thread(() -> {
                channelManager.getChannels();
                channelManager.getHealthyChannels();
                channelManager.getLoadBalancer();
            });
            threads[i].start();
        }

                }
            });
            readThreads[i].start();
        }

        // Wait for all threads
        for (Thread thread : updateThreads) {
            thread.join(5000);
        }
        for (Thread thread : readThreads) {
            thread.join(5000);
        }

        // Verify final state
        assertEquals(100, entry.getChildren().size());

                    }
                });
            }

            // Start all threads
            for (Thread t : threads) {
                t.start();
            }

            // Wait for completion
            for (Thread t : threads) {
                t.join();
            }

            // Verify thread safety - no unexpected exceptions

                }
            }
        } catch (final InterruptedException e) {
            logger.warn("Interrupted to generate a thumbnail of {}: {}", thumbnailId, cmdList, e);
            Thread.currentThread().interrupt();
        } catch (final Exception e) {
            logger.warn("Failed to generate a thumbnail of {}: {}", thumbnailId, cmdList, e);
        } finally {
            if (task != null) {

    assertThat(c1.noNewExchanges).isTrue()
  }

  @Test fun interruptStopsThread() {
    val taskRunnerThreads = mutableListOf<Thread>()
    val taskRunner =
      TaskRunner(
        RealBackend { runnable ->
          Thread(runnable, "interruptStopsThread TaskRunner")
            .also { taskRunnerThreads += it }
        },
      )

    val pool =
      factory.newConnectionPool(