change output order

Author: wasabeef

example/lib/gen/assets.gen.dart

@@ -60,6 +60,9 @@ String generateAssets(File pubspecFile, DartFormatter formatter,
     }
   }
 
+  classesBuffer.writeln(_assetsClassDefinition(assetsStaticStatements));
+  classesBuffer.writeln(_assetGenImageClassDefinition);
+
   final imports = <String>{'package:flutter/widgets.dart'};
   integrations.forEach((integration, enabled) {
     if (enabled) {
@@ -71,9 +74,6 @@ String generateAssets(File pubspecFile, DartFormatter formatter,
     importsBuffer.writeln(import(package));
   }
 
-  classesBuffer.writeln(_assetsClassDefinition(assetsStaticStatements));
-  classesBuffer.writeln(_assetGenImageClassDefinition);
-
   final buffer = StringBuffer();
   buffer.writeln(header);
   buffer.writeln(importsBuffer.toString());