If you are familiar with WinDBG, you can break the process in the debugger at the debug output and check the column.
To do this in WinDBG, join your process and go to Debug-> Event Filters
Find the line with the inscription "Debugee output" and click on it. On the right button "Enabled" at runtime
Type g at the command line to start the debugger, and when it breaks into the correct output, use kb to print an unmanaged call or .loadby sos clr! clrstack for printing managed calls
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