title: How to disable previous dates in DateTimeRangePicker?
body: <p>I'm using f_datetimerangepicker library for selecting date range. I want to disable previous dates. How to do it if we are using this library?</p>
  <pre><code>    DateTimeRangePicker(
                          startText: &quot;From&quot;,
                          endText: &quot;To&quot;,
                          doneText: &quot;Confirm&quot;,
                          cancelText: &quot;Cancel&quot;,
                          interval: 5,
                          minimumTime: DateTime.now(),
                          initialStartTime: DateTime.now(),
                          initialEndTime: DateTime.now().add(Duration(days: 30)),
                          mode: DateTimeRangePickerMode.date,
                          use24hFormat: false,
                          onConfirm: (start, end) {
                            print(start);
                            print(end);
                          }).showPicker(context);
  </code></pre>