title: How to disable Flutter sound-safety and null-safety for the SplashScreen library?
body: <p>I am trying to run the SplashScreen library but it isn't working.
  I have edited the package’s pubspec.yaml file, setting the minimum SDK constraint to 2.7.0,
  It brought out this error:</p>
  <blockquote>
  <p>lib/mySplashScreen.dart:5:28: Error: Null safety features are disabled
  for this library. Try removing the package language version or setting
  the language version to 2.12 or higher.   const MySplashScreen({Key?
  key}) : super(key: key);
  ^ Error: Cannot run with sound null safety, because the following dependencies don't support null safety:</p>
  <ul>
  <li>package:ar_app</li>
  <li>package:splashscreen For solutions, see <a href="https://dart.dev/go/unsound-null-safety" rel="nofollow noreferrer">https://dart.dev/go/unsound-null-safety</a></li>
  </ul>
  </blockquote>
  <p>I added a language version comment to the top of the Dart files, ie: // @dart=2.9
  It brought this error:</p>
  <blockquote>
  <p>Error: A library can't opt out of null safety by default, when using
  sound null safety. // @dart=2.9 ^^^^^^^^^^^^</p>
  </blockquote>
  <p>What do I do?</p>