title: Retrofit2 MySQL duplicated @POST requests with new Android Studio 3.6
body: <p>so long...</p>
  
  <p>I´m getting mad about an Android Studio 3.6 update.
  I didn´t touch the code during update. Before, it was working all fine, but when updated to 3.6, it seems Retrofit2 makes my @POST in client repeat, so if I´m tying to add a new user to DB, it inserts, but then do it some more times, so I get into response failure, and so it says "user already exists". As I said it´s not a coding matter, as it worked fine until update.
  Anyone cry with me?
  Thanks</p>