title: How do you determine if a variable is "callable" in dart?
body: <p>I am doing a small experiment in dart and I couldn't find a way to determine if a variable is "callable" without explicitly checking for each type (String, int, bool, ect) and guessing that it was callable if it was none of those. I also experimented with a try/catch which to me just seems wrong.</p>
  
  <p>Whats the right way or at least the best way to make that determination?</p>
  
  <p>Here is an example I did to show what I am trying to accomplish:
  <a href="https://gist.github.com/digitalfiz/3f431dc07ca761389062" rel="nofollow">https://gist.github.com/digitalfiz/3f431dc07ca761389062</a></p>