zIndex for Toaster

Currently for some reason it's not possible to change zIndex for Toaster component. But it's very likely to be possible. The documentation says that this component has a property called zIndex, but as I said it's impossible to use it:

One of possible solutions:

import Toaster from 'evergreen-ui/src/toaster/src'
const toaster = new Toaster({ zIndex: 40 })
toaster.danger('Error occurred!')

Another solution:

import { toaster } from 'evergreen-ui'
toaster.danger('Error occurred', { zIndex: 40 })