}

        @Override
        public void notifyNewValue(Object newValue) {}
      };

  /** Singleton placeholder that indicates a value is being loaded. */
  @SuppressWarnings("unchecked") // impl never uses a parameter or returns any non-null value
  static <K, V> ValueReference<K, V> unset() {
    return (ValueReference<K, V>) UNSET;
  }

    ReferenceEntry<Object, Object> entry = segment.getEntry(one, hash);
    ReferenceEntry<Object, Object> newEntry = segment.copyEntry(entry, null);
    table.set(index, newEntry);

    @SuppressWarnings("unchecked")
    LoadingValueReference<Object, Object> valueReference =
        (LoadingValueReference) newEntry.getValueReference();
    assertFalse(valueReference.futureValue.isDone());
    startSignal.countDown();

    ReferenceEntry<Object, Object> entry = segment.getEntry(one, hash);
    ReferenceEntry<Object, Object> newEntry = segment.copyEntry(entry, null);
    table.set(index, newEntry);

    @SuppressWarnings("unchecked")
    LoadingValueReference<Object, Object> valueReference =
        (LoadingValueReference) newEntry.getValueReference();
    assertFalse(valueReference.futureValue.isDone());
    startSignal.countDown();

        }

        @Override
        public void notifyNewValue(Object newValue) {}
      };

  /** Singleton placeholder that indicates a value is being loaded. */
  @SuppressWarnings("unchecked") // impl never uses a parameter or returns any non-null value
  static <K, V> ValueReference<K, V> unset() {
    return (ValueReference<K, V>) UNSET;
  }

      public Object apply(Entry<?, ?> entry) {
        return entry.getValue();
      }
    };
  }

  @SuppressWarnings("unchecked")
  static <K extends @Nullable Object> Function<Entry<K, ?>, K> keyFunction() {
    return (Function) EntryFunction.KEY;
  }

  @SuppressWarnings("unchecked")
  static <V extends @Nullable Object> Function<Entry<?, V>, V> valueFunction() {
    return (Function) EntryFunction.VALUE;
  }

               * RuntimeException and IOException because `closeable` has type `Closeable`—except
               * that we have to account for sneaky checked exception.
               */
              restoreInterruptIfIsInterruptedException(e);
              logger.get().log(WARNING, "thrown by close()", e);
            }
          });