*
   * @param key the non-null key whose value should be loaded
   * @param oldValue the non-null old value corresponding to {@code key}
   * @return the future new value associated with {@code key}; <b>must not be null, must not return
   *     null</b>
   * @throws Exception if unable to reload the result

 * any type to which the event is assignable. This includes implemented interfaces, all
 * superclasses, and all interfaces implemented by superclasses.
 *
 * <p>When {@code post} is called, all registered subscribers for an event are run in sequence, so
 * subscribers should be reasonably quick. If an event may trigger an extended process (such as a

// underlying writer. It should be used when the zip data is appended to an
// existing file, such as a binary executable.
// It must be called before any data is written.
func (w *Writer) SetOffset(n int64) {
	if w.cw.count != 0 {
		panic("zip: SetOffset called after data was written")
	}
	w.cw.count = n
}

// Flush flushes any buffered data to the underlying writer.

      } else {
        return EventListener.NONE;
      }
    }
  };

  ...
}
```

### Events with Failures

When an operation fails, a failure method is called. This is `connectFailed()` for failures while building a connection to the server, and `callFailed()` when the HTTP call fails permanently. When a failure happens it is possible that a `start` event won’t have a corresponding `end` event.

    CLOSED,

    /**
     * {@link ClosingFuture#finishToValueAndCloser(ValueAndCloserConsumer, Executor)} has been
     * called. The step may not be further subsumed, nor may {@link #finishToFuture()} be called.
     */
    WILL_CREATE_VALUE_AND_CLOSER,
  }

    throw new IOException("reset not supported");
  }

  /**
   * Returns the {@link HashCode} based on the data read from this stream. The result is unspecified
   * if this method is called more than once on the same instance.
   */
  public HashCode hash() {
    return hasher.hash();
  }

// UpdateWorkers at the end of this function leaves n goroutines waiting for
// transition tasks
func (t *transitionState) UpdateWorkers(n int) {
	t.mu.Lock()
	defer t.mu.Unlock()
	if t.objAPI == nil { // Init hasn't been called yet.
		return
	}
	t.updateWorkers(n)
}

func (t *transitionState) updateWorkers(n int) {
	if n == 0 {
		n = 100
	}

	for t.numWorkers < n {
		go t.worker(t.objAPI)
		t.numWorkers++

 *         .header("Proxy-Authorization", "secret")
 *         .build();
 *   }
 * }
 * return null; // Didn't find a preemptive auth scheme.
 * ```
 *
 * ## Reactive Authentication
 *
 * Implementations authenticate by returning a follow-up request that includes an authorization
 * header, or they may decline the challenge by returning null. In this case the unauthenticated
 * response will be returned to the caller that triggered it.
 *

    int listenerCount = 20;
    CountDownLatch listenerLatch = new CountDownLatch(listenerCount);

    // Test that listeners added both before and after the value is available
    // get called correctly.
    for (int i = 0; i < 20; i++) {

      // Right in the middle start up a thread to close the latch.
      if (i == 10) {
        new Thread(() -> latch.countDown()).start();
      }

 *   <dt>{@link BiMap}
 *   <dd>An extension of {@link java.util.Map} that guarantees the uniqueness of its values as well
 *       as that of its keys. This is sometimes called an "invertible map," since the restriction on
 *       values enables it to support an {@linkplain BiMap#inverse inverse view} -- which is another
 *       instance of {@code BiMap}.
 *   <dt>{@link Table}