title: React Native packager is caching old versions of my files
body: <p>I'm using Exponent but I believe this to be caused by the React Native packager under the hood.</p>
  
  <p>Quite frequently if I introduce an error to my code I'll get the red box (as expected). However, at that point the packager seems to freeze in time. Changing the affected file to fix the issue does nothing. I just get the same red box error.</p>
  
  <p>Watchman seems to be working fine, the app attempts to refresh if I change the file. I've also tried clearing the Watchman cache.</p>
  
  <p>If I wait for 1-2 hours the issue resolves itself. It seems to be a caching issue somewhere.</p>
  
  <p>We're using MobX. Not sure if that's an important detail.</p>