title: java.time equivalent of Joda-Time `withTimeAtStartOfDay`? (get first moment of the day)
body: <p>In the <a href="http://www.joda.org/joda-time/">Joda-Time</a> library, the <a href="http://www.joda.org/joda-time/apidocs/org/joda/time/DateTime.html"><code>DateTime</code></a> class offers a method <a href="http://www.joda.org/joda-time/apidocs/org/joda/time/DateTime.html#withTimeAtStartOfDay--"><code>withTimeAtStartOfDay</code></a> to get the first moment of the day. You might think of that moment as "midnight". That first moment is usually the time <code>00:00:00.000</code> but not always.</p>
  
  <p>Does the <a href="http://docs.oracle.com/javase/8/docs/api/java/time/package-summary.html">java.time package</a> found in Java 8 and later have an equivalent feature?</p>