title: How can I make Array (list) Elements Unique in Dart?
body: <p>I need to remove <strong>redundant</strong> (String) elements from a list.  Or perhaps to prevent them from being entered in the first place is the better solution?  Sets do not allow duplicates, but they also do not keep order and I need the order.  This is a common problem for me so I am looking for a possible language solution for full efficiency.</p>
  
  <p>(In the past I have extended an Array Class to add my own add_unique() method, but this seems like it is a common enough issue to be handled by the language and likely more efficiently.)</p>
  
  <p>Thanks,</p>
  
  <p>_g</p>