minor changes

packages/stream_chat_localizations/lib/src/stream_chat_localizations.dart

@@ -30,15 +30,15 @@ const kStreamChatSupportedLanguages = {'en'};
 /// Generally speaking, this method is only intended to be used by
 /// [GlobalStreamChatLocalizations.delegate].
 GlobalStreamChatLocalizations? getStreamChatTranslation(Locale locale) {
+  final languageCode = locale.languageCode;
+  assert(
+    kStreamChatSupportedLanguages.contains(languageCode),
+    'getStreamChatTranslation() called for unsupported locale "$locale"',
+  );
   switch (locale.languageCode) {
     case 'en':
       return const StreamChatLocalizationsEn();
   }
-  assert(
-  false,
-  'getStreamChatTranslation() called for unsupported locale "$locale"',
-  );
-  return null;
 }
 
 /// Implementation of localized strings for the stream chat widgets
@@ -134,8 +134,7 @@ class _StreamChatLocalizationsDelegate
     assert(isSupported(locale), '');
     return _loadedTranslations.putIfAbsent(
       locale,
-          () =>
+      () => SynchronousFuture<StreamChatLocalizations>(
-          SynchronousFuture<StreamChatLocalizations>(
         getStreamChatTranslation(locale)!,
       ),
     );