title: xarray autocomplete trigger computation
body: <p>When using xarray in interactive Python shell, pressing tab for autocomplete can trigger computation of values unintentionally.</p>
  <p>MWE:</p>
  <pre><code>import dask
  import dask.array
  import xarray as xr
  
  if __name__ == '__main__':
      from dask.distributed import Client
      client = Client()
      print(client.dashboard_link)
      ## Test memory management of just dask.array + xr.DataArray
      da = xr.DataArray(
          data = dask.array.random.random(size=(10000,10000))
      )
      ## now type 'da.val' and press tab for autocomplete
      ## don't forget to open the dashboard first
  </code></pre>
  <p>How can this behaviour be avoided?</p>