title: ICS will adjust date when add to calendar base on timezone
body: <p>I've downloaded a PHP script that allow me to generate downloadable ICS for a scheduled webinar. Date &amp; time is set to WP ACF post. Also, WordPress timezone was set to America/Los_Angeles. But my timezone is based in Manila, PH.</p>
  
  <p>Here's the code.</p>
  
  <pre><code>// ACF Date
  $wdate = get_sub_field('date'); // Tuesday, June 16, 2020
  $stime = get_sub_field('start_time'); // 11:00 am
  $etime = get_sub_field('end_time'); // 11:30 am
  
  // Prepare Date using date_i18n()
  // Starting DateTime
  $st_gmt = $wdate.' '.$stime;
  $st = get_date_from_gmt($st_gmt, 'Y-m-d H:i:s');
  $date_start = date_i18n(get_option('date_format').' '.get_option('time_format'), strtotime($st));
  // Output: June 16, 2020 11:00 AM
  
  // Ending DateTime
  $et_gmt = $wdate.' '.$etime;
  $et = get_date_from_gmt($et_gmt, 'Y-m-d H:i:s');
  $date_end = date_i18n(get_option('date_format').' '.get_option('time_format'), strtotime($et));
  // Output: June 16, 2020 11:30 AM
  </code></pre>
  
  <p>Whenever I test downloading the .ics calendar file, which it should be <code>June 17, 2020 2:00 AM &amp; June 17, 2020 2:30 AM</code> but the output is always set to <code>June 16, 2020 7:00 PM &amp; June 16, 2020 7:30 PM</code> since I am based from Manila, PH while the event was set to Los Angeles. </p>
  
  <p>Here's the output from actual ICS file.</p>
  
  <pre><code>BEGIN:VCALENDAR
  VERSION:2.0
  X-WR-TIMEZONE:America/Los_Angeles
  PRODID:-//hacksw/handcal//NONSGML v1.0//EN
  CALSCALE:GREGORIAN
  BEGIN:VTIMEZONE
  TZID:America/Los_Angeles
  END:VTIMEZONE
  BEGIN:VEVENT
  LOCATION:Webinar Zoom
  DESCRIPTION:This is my description
  DTSTART:20200616T110000Z
  DTEND:20200616T113000Z
  SUMMARY:This is my summary
  URL;VALUE=URI:
  DTSTAMP:20200603T051015Z
  UID:5ed6c0375fbf6
  END:VEVENT
  END:VCALENDAR
  </code></pre>
  
  <p><strong>Question:</strong> How can I output the ics file to match users timezone when they download the file and add to their calendar?</p>