n call. Remember the <code>transform</code> API only
supports stateless transformations. You could also implement much more complicated stateful transformations, like implementing your own aggregation
function if you are not satisfied with Quokka's default operator's performance.</p>
<p>This API is still being finalized. A version of it that takes multiple input streams is also going to be added. This is the part of the DataStream level 
api that is closest to the underlying execution engine. Quokka's under