rmations. You could also implement much more complicated stateful transformations, like implementing your own aggregation</span>
<span class="sd">    function if you are not satisfied with Quokka&#39;s default operator&#39;s performance.</span>

<span class="sd">    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 </span>
<span class="sd">    api that is closest to the underlying execution engine. Quokka&