title: Dask: Getting the Row which has the max value in groups using groupby
body: <p>The same problem can be solved in Pandas using <em>transform</em> as explained <a href="https://stackoverflow.com/a/28175722/4819376">here</a> 
  With dask the only working <a href="https://stackoverflow.com/a/21709413/4819376">solution</a> I found use merge. And I was wondering if there are other ways to achieve it.</p>