title: What to use in place of RetrofitError.Kind.NETWORK for new Retrofit 2 API?
body: <p>In Retrofit 1.9.x there was a <code>RetrofitError.Kind.NETWORK</code> that let you easily determine whether the failure was due to a network error or not. In the new 2.0 API we no longer have <code>RetrofitError</code> is there a simple equivalent we can use to test whether the <code>Response</code> failed due to the network?</p>