Periodically sending data from database to an API
If Dowork takes longer than 15 seconds to execute, it will be called a second time.  Will this cause issues?  One way around that would be to disable the timer while you're doing work, then start it up again when the work is done, or add an appropriately typed and thread safe "busy" member to the class so that you can skip starting any new work if work is currently being done.