How to determine if files are in sync using API

[calmh (Jakob Borg)]

The API:

https://docs.syncthing.net/dev/rest.html

A similar discussion from the other day:

How to find if local changes have been synced at remote ?

I have a setup with two system only. I am writing a program where, when user clicks a button on local machine, i trigger scan via POST /rest/db/scan to capture the changes made since last scan. Now, in my program, I need to wait till the local detected changes are synced on a remote machine. How can i reliably find that my remote device is updated to latest version. Can i use ‘GET /rest/db/completion’ for this or can anyone suggest other way ?