title: When should `DateTime.now.utc` vs. `Time.current.utc` be used in Rails?
body: <p>In Rails, I'm a little confused on the guidance between when to use DateTime.now.utc and Time.current. There seem to be differing opinions inside the framework about which is best, particularly in different versions.</p>
  
  <p>It looks like <code>DateTime.now.utc</code> produces a timestamp with a <em>UTC offset of zero</em>, while <code>Time.current.utc</code> produces a timestamp with a <em>time zone of UTC</em>. That seems like a subtle distinction but it's pretty important in many cases (e.g. DST calculations).</p>
  
  <p>When should you use <code>DateTime.now.utc</code>, and when should you use <code>Time.current.utc</code>? Is there any reason to use <code>DateTime.now.utc</code> instead of <code>Time.current.utc</code>?</p>