title: Convert date to milliseconds in laravel using Carbon
body: <p>i make a date in laravel with carbon </p>
  
  <pre><code>$date = Carbon::createFromDate(2018,02,16);
  </code></pre>
  
  <p>how should i change it to milliseconds?</p>
  
  <p>something like this:</p>
  
  <pre><code>18:16:30 -&gt; 1532785457060
  </code></pre>