title: What exactly does volley.VolleyError.NetworkError mean in android?
body: <p>I am a bit confused about volley NetworkError, and about the difference between NetworkError and NoConnectionError. The doc says this about NetworkError -</p>
  
  <blockquote>
    <p>Indicates that there was a network error when performing a Volley
    request.</p>
  </blockquote>
  
  <p>What do they mean by "network error"? When is NoConnectionError raised and when is NetworkError raised?</p>