return loadSync(key, hash, loadingValueReference, loader);
          }
        } finally {
          statsCounter.recordMisses(1);
        }
      } else {
        // The entry already exists. Wait for loading.
        return waitForLoadingValue(e, key, valueReference);
      }
    }

    V waitForLoadingValue(ReferenceEntry<K, V> e, K key, ValueReference<K, V> valueReference)

      @Override
      public ListenableFuture<V> apply(X t) {
        throw newAssertionError("Unexpected fallback", t);
      }
    };
  }

  /** Alternative to AssertionError(String, Throwable), which doesn't exist in GWT 2.6.1. */
  private static AssertionError newAssertionError(String message, Throwable cause) {
    AssertionError e = new AssertionError(message);
    e.initCause(cause);
    return e;
  }

          }

          @Override
          public String toString() {
            return function.toString();
          }
        };
    // TODO(dpb): Switch to future.transformSync when that exists (passing a throwing function).
    return derive(future.transformAsync(applyFunction, executor));
  }

  /**
   * Returns a new {@code ClosingFuture} pipeline step derived from this one by applying a function

            return loadSync(key, hash, loadingValueReference, loader);
          }
        } finally {
          statsCounter.recordMisses(1);
        }
      } else {
        // The entry already exists. Wait for loading.
        return waitForLoadingValue(e, key, valueReference);
      }
    }

    V waitForLoadingValue(ReferenceEntry<K, V> e, K key, ValueReference<K, V> valueReference)

      @Override
      public ListenableFuture<V> apply(X t) {
        throw newAssertionError("Unexpected fallback", t);
      }
    };
  }

  /** Alternative to AssertionError(String, Throwable), which doesn't exist in GWT 2.6.1. */
  private static AssertionError newAssertionError(String message, Throwable cause) {
    AssertionError e = new AssertionError(message);
    e.initCause(cause);
    return e;
  }