*
   * @param listener the listener to run when the service changes state is complete
   * @param executor the executor in which the listeners callback methods will be run. For fast,
   *     lightweight listeners that would be safe to execute in any thread, consider {@link
   *     MoreExecutors#directExecutor}.
   * @since 13.0
   */
  void addListener(Listener listener, Executor executor);

  /**
   * The lifecycle states of a service.

     * hold the synchronizer. This synchronizer is used to implement the blocking and waiting calls
     * as well as to handle state changes in a thread-safe manner. The current state of the future
     * is held in the Sync state, and the lock is released whenever the state changes to {@link
     * #COMPLETED}, {@link #CANCELLED}, or {@link #INTERRUPTED}
     *

func (target *KafkaTarget) Close() error {
	close(target.quitCh)

	if target.batch != nil {
		target.batch.Close()
	}

	if target.producer != nil {
		if target.store != nil {
			// It is safe to abort the current transaction if
			// queue_dir is configured
			target.producer.AbortTxn()
		} else {
			target.producer.CommitTxn()
		}
		target.producer.Close()
		return target.client.Close()
	}

Since HTTP requests frequently happen in parallel, connection pooling must be thread-safe.

These are the primary classes involved with establishing, sharing, and terminating connections:

      throw new IllegalArgumentException(e);
    }

    boolean empty;
    if (effectiveRange.isEmpty()) {
      empty = true;
    } else {
      /*
       * requireNonNull is safe because the effectiveRange operations above would have thrown or
       * effectiveRange.isEmpty() would have returned true.
       */
      C afterLower = requireNonNull(range.lowerBound.leastValueAbove(domain));

import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

/**
 * Cache entry for directory contents with thread-safe operations
 */
public class DirectoryCacheEntry {

    private final String directoryPath;
    private final Smb2LeaseKey leaseKey;
    private final long createTime;
    private volatile long lastUpdateTime;

        return o != null;
      }

      @Override
      public String toString() {
        return "Predicates.notNull()";
      }
    };

    @SuppressWarnings("unchecked") // safe contravariant cast
    <T extends @Nullable Object> Predicate<T> withNarrowedType() {
      return (Predicate<T>) this;
    }
  }

  /**
   * @see Predicates#not(Predicate)
   */

### 추가 선택적 의존성 { #additional-optional-dependencies }

추가로 설치하고 싶을 수 있는 의존성도 있습니다.

추가 선택적 Pydantic 의존성:

* [`pydantic-settings`](https://docs.pydantic.dev/latest/usage/pydantic_settings/) - 설정 관리를 위한 것입니다.
* [`pydantic-extra-types`](https://docs.pydantic.dev/latest/usage/types/extra_types/extra_types/) - Pydantic에서 사용할 추가 타입을 위한 것입니다.

추가 선택적 FastAPI 의존성:

* [`orjson`](https://github.com/ijl/orjson) - `ORJSONResponse`를 사용하려면 필요.

 * </ul>
 *
 * <p>
 * The class also supports FTP authentication via {@link FtpAuthenticationHolder}, which stores
 * authentication details for different FTP URLs.
 * </p>
 *
 * <p>
 * Usage example:
 * </p>
 *
 * <pre>
 * {@code
 * FtpClient ftpClient = new FtpClient();
 * ftpClient.init(); // Initialize with configured parameters

      /*
       * uncheckedCastNullableTToT is safe: The first call to this method always enters the !hasNext() case and
       * populates key, after which it's never cleared.
       */
      return output(uncheckedCastNullableTToT(key), valueIterator.next());
    }

    @Override
    public void remove() {
      valueIterator.remove();
      /*