title: Behavior in reactive-banana
body: <p>Pardon me, I'm just starting to look into reactive-banana and FRP.</p>
  
  <p>The author of reactive-banana made <a href="https://github.com/HeinrichApfelmus/Haskell-BlackBoard/blob/master/reactive-banana-wx/src/Counter.hs">this</a> example per my suggestion, in which he creates a counter which can be increased and decreased. He uses accumE function which accumulates events. I think I was able to somewhat grok the Event type, and was able to test quite a few things with it, but then I remembered that there was also Behavior. I looked into it, but it seems like the behavior is meant to be used in similar situations; to modify an existing variable, just like accumE does with events.</p>
  
  <p>What does Behavior mean, and what are the use cases for it?</p>