}
    CyclicBarrier barrier =
        new CyclicBarrier(
            6 // for the setter threads
                + 50 // for the listeners
                + 50 // for the blocking get threads,
                + 1); // for the main thread
    ExecutorService executor = newFixedThreadPool(barrier.getParties());
    AtomicReference<AbstractFuture<String>> currentFuture = Atomics.newReference();

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3

import okio.IOException

/**
 * Returns the trailers that follow an HTTP response, blocking if they aren't ready yet.
 * Implementations of this interface should respond to [Call.cancel] by immediately throwing an
 * [IOException].
 *

 *
 * <p>An instance may be called concurrently by multiple threads to process different entries.
 * Implementations of this interface should avoid performing blocking calls or synchronizing on
 * shared resources.
 *
 * @param <K> the most general type of keys this listener can listen for; for example {@code Object}
 *     if any key is acceptable

   *
   * <p>Currently, this method is invoked while holding a lock. If an implementation of this method
   * blocks, it can prevent this service from changing state. If you need to performing a blocking
   * operation in order to trigger shutdown, consider instead registering a listener and
   * implementing {@code stopping}. Note, however, that {@code stopping} does not run at exactly the

    // thread because the task will block on the task latch after unblocking
    // the run latch.
    exec.execute(task);
    runLatch.await();
    assertEquals(1, listenerLatch.getCount());
    assertFalse(task.isDone());
    assertFalse(task.isCancelled());

    // Finish the task by unblocking the task latch.  Then wait for the
    // listener to be called by blocking on the listener latch.
    taskLatch.countDown();

import java.util.concurrent.TimeUnit;
import org.jspecify.annotations.NullUnmarked;
import org.jspecify.annotations.Nullable;

/**
 * An unbounded {@linkplain BlockingQueue blocking queue} that uses the same ordering rules as class
 * {@link PriorityQueue} and supplies blocking retrieval operations. While this queue is logically
 * unbounded, attempted additions may fail due to resource exhaustion (causing {@code

 *     failed connect attempts (such as trying the next [ConnectionSpec]), or as attempts that lost
 *     a race in fast follow-up.
 *
 *  4. If there's no existing connection, make a list of routes (which may require blocking DNS
 *     lookups) and attempt new connections to them. When failures occur, retries iterate the
 *     list of available routes.
 *

 * Fix bug where the Content-Length header was not always dropped when
   following a redirect from a POST to a GET.
 * Implement basic support for `Thread.interrupt()`. OkHttp now checks
   for an interruption before doing a blocking call. If it is interrupted,
   it throws an `InterruptedIOException`.

## Version 1.5.2

_2014-03-17_

 * Fix bug where deleting a file that was absent from the `HttpResponseCache`
   caused an IOException.

        } finally {
          taskRunner.withLock {
            activeThreads--
            startNextTask()
          }
        }
      }
    }
  }

  /**
   * This blocking queue hooks into a fake clock rather than using regular JVM timing for functions
   * like [poll]. It is only usable within task faker tasks.
   */
  private inner class TaskFakerBlockingQueue<T>(

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.io.Serializable;
import java.util.ArrayDeque;
import java.util.Collection;
import java.util.Queue;

/**
 * A non-blocking queue which automatically evicts elements from the head of the queue when
 * attempting to add new elements onto the queue and it is full. This queue orders elements FIFO