title: React Select - type to search - Access to filterOption resulting array
body: <p>In React Select, my understanding is that I can provide the prop <code>options</code> to give an initial array of options to the select menu. Another prop that I am using is <code>filterOption</code> which I understand to be used in a map over all the initial options and called when user types to search.</p>
  
  <p>My question is this: Is there a way for me to check the array of filtered options that react select is building while react select is doing the filtering?</p>
  
  <p>I ask this because I have some options which have differing search key values but identical display values for business reasons. I want to be able to add a conditional statement (probably in filterOption?) that checks if the current item has the same display key as something that has already passed react select's filter.</p>
  
  <p>Thanks!</p>