Robert,
_onSearchResults function is called after search is finished. 'evt' object has seachresults object and search string.
I have configured all layers of my webmap in search widget (around 30). It takes around 35-45 seconds to finish search on all the layers and then it returns all results at once in _onSearchResults function. Because of this behavior, user has to wait for that much time. Instead I wanted to check if there is anyway to get search result one by one and process it. In that way, atleast user can see the progress instead of waiting for all the search results at once.