title: What is the difference between "yield return 0" and "yield return null" in Coroutine?
body: <p>I'm new and a bit confused about "<code>yield</code>". But finally I understand how it worked using <code>WaitForSeconds</code></p>
  
  <p>but I can't see the difference between of "<code>yield return 0</code>" and "<code>yield return null</code>". </p>
  
  <p>are both them waiting for the next frame to execute?</p>
  
  <p>sorry for my bad English. Thank you very much.</p>