if (actualException instanceof InterruptedException) {
        return Outcome.INTERRUPT;
      } else {
        throw newAssertionError("unexpected exception", targetException);
      }
    } catch (IllegalAccessException e) {
      throw newAssertionError("unexpected exception", e);
    }
  }

  private void enterSatisfyGuardAndLeaveInCurrentThread() {
    monitor.enter();
    try {

      if (actualException instanceof InterruptedException) {
        return Outcome.INTERRUPT;
      } else {
        throw newAssertionError("unexpected exception", targetException);
      }
    } catch (IllegalAccessException e) {
      throw newAssertionError("unexpected exception", e);
    }
  }

  private void enterSatisfyGuardAndLeaveInCurrentThread() {
    monitor.enter();
    try {

    return new AsyncFunction<X, V>() {
      @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 new AsyncFunction<X, V>() {
      @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);