Hide an element until its DataSource is ready

<Component name="Test" var.nonce="{0}">

<DataSource
  id="fruits"
  url="/api/fruits?{nonce}"
  inProgressNotificationMessage="Loading fruits"
  when="{nonce > 0}"
  />

<Button
  label="Run"
  onClick="{nonce++}"
/>

<Fragment when="{fruits.loaded}">
  <Text>Fruits: {fruits.value.length} found</Text>
</Fragment>

</Component>