Attempt at making pull() be called every time something is enqueued or d...

...equeued in RS. See #189.
OK I can confirm it does not (UGH). This caught a bug:

```
not ok 83 enqueue after error must throw that error
  ---
    operator: throws
    expected:
      '/i am sad/'
    actual:
      { [TypeError: Cannot read property '_storedError' of undefined] message: 'Cannot read property \'_storedError\' of undefined' }
  ...
```