I filed a prior ThreadLeak:
Thread leak in JustMock (telerik.com)
I think I've found another one: (VS version 16.10.31321.278)
Apparently, the MonitorTimer_Elapsed code is running on a threadpool thread and it takes longer than 1 sec (perhaps it's waiting on a lock?).
Another timer tick occurs and the method is called again. Eventually, the ThreadPool runs out of threads and grows by about 1 thread per second (1Mb /sec leak)
In one dump 2Gig was used (1962 threads on the same MonitorTimer_Elapsed stack frame)
In that same dump there were 52 stacks with this frame:
(this was the same item as my prior report).