ios – Flutter – how get default system font?

I utilizing customized font for my Flutter app:

return MaterialApp (
      theme: ThemeData(
        fontFamily: "MyFont" 
      ) 
   )

however in a single place of software I would like to make use of “system font”. that is particularly essential for iOS (Sf Professional). If I perceive appropriately, that is the system font for iOS. However how can I exploit “system font” if I already use “customized font” at software stage?

I attempted:

ultimate fontFamily = DefaultTextStyle.of(context).fashion!.fontFamily;

However this code return “MyFont”.

additionally I attempted importing from apple web site. however there is just one large SF-Professional.ttf(8Mb) file contained in the picture. Not – SFPro-Common.ttf, SFPro-SemiBold.ttf … Flutter doesn’t help .otf information.

Tips on how to resolve this drawback? any recommendation I will likely be grateful