an hour or so, and were quite dry again, the Dodo suddenly called
out `The race is over!' and they all crowded round it, panting,
and asking, `But who has won?'

  This question the Dodo could not answer without a great deal of
thought, and it sat for a long time with one finger pressed upon
its forehead (the position in which you usually see Shakespeare,
in the pictures of him), while the rest waited in silence.  At

      assertFalse("Listener called more than once", wasCalled());
      called.set(true);
    }

    public void expectCall() {
      assertFalse("expectCall is already true", expectCall);
      expectCall = true;
    }

    public boolean wasCalled() {
      return called.get();
    }
  }

  public void testAllAsList() throws Exception {

      assertFalse("Listener called more than once", wasCalled());
      called.set(true);
    }

    public void expectCall() {
      assertFalse("expectCall is already true", expectCall);
      expectCall = true;
    }

    public boolean wasCalled() {
      return called.get();
    }
  }

  public void testAllAsList() throws Exception {

     * purposes, the "count" field, tracking the number of elements, serves as that volatile
     * variable ensuring visibility. This is convenient because this field needs to be read in many
     * read operations anyway:
     *
     * - All (unsynchronized) read operations must first read the "count" field, and should not look
     * at table entries if it is 0.
     *

   *
   * <p>If this {@code ClosingFuture} fails with an exception of the given type, the derived {@code
   * ClosingFuture} will be equivalent to the one returned by the function.
   *
   * <p>If this {@code ClosingFuture} succeeds or fails with a different exception type, the
   * function will not be called, and the derived {@code ClosingFuture} will be equivalent to this
   * one.
   *

     * purposes, the "count" field, tracking the number of elements, serves as that volatile
     * variable ensuring visibility. This is convenient because this field needs to be read in many
     * read operations anyway:
     *
     * - All (unsynchronized) read operations must first read the "count" field, and should not look
     * at table entries if it is 0.
     *

an hour or so, and were quite dry again, the Dodo suddenly called
out `The race is over!' and they all crowded round it, panting,
and asking, `But who has won?'

  This question the Dodo could not answer without a great deal of
thought, and it sat for a long time with one finger pressed upon
its forehead (the position in which you usually see Shakespeare,
in the pictures of him), while the rest waited in silence.  At

    return new IdentityHashMap<>();
  }

  /**
   * Computes the difference between two maps. This difference is an immutable snapshot of the state
   * of the maps at the time this method is called. It will never change, even if the maps change at
   * a later time.
   *
   * <p>Since this method uses {@code HashMap} instances internally, the keys of the supplied maps