I believe that's for EE and work permit applicants. Few months back I thought of doing the same but clinics told me IRCC has clearly outlined that for QSW applicants you need the request prior to doing medical. On the other hand, there's no point sending medicals if the officer isn't looking at your file anyways. Besides, it takes less than 2 weeks to go from medical request being received and then medical passed so I decided to wait and eventually after 25 months of waiting got the medical request.