title: Create dask list for dask dataframe column
body: <p>I want to have a list of the unique values of a column of dask dataframe  . Using compute() after unique() is working but it takes a lot of time and there is no paralleling.</p>
  
  <pre class="lang-py prettyprint-override"><code>
  data = {'Name':['Tom', 'nick', 'krish', 'jack', 'krish', 'jack'], 'Age':[20, 21, 19, 18, 25, 31]} 
  
  # Create DataFrame 
  df = pd.DataFrame(data) 
  df = dd.from_pandas(df, npartitions=3)
  
  list=df.Name.unique().compute()
  </code></pre>
  
  <p>What I am trying to have is a dask list without using the compute having</p>
  
  <pre class="lang-py prettyprint-override"><code>list=['Tom', 'nick', 'krish', 'jack']
  </code></pre>