Fix crash on shutdown when using global recording stream variables in C++

[Wumpf]

What

• Fixes C++ SDK crash on shutdown #5260
  • recently duplicated as Panic upon exiting program if a recording is stored in a global variable #5697)

Was able to repro this on Mac but not on Windows. Fix is a bit wonky but worked reliably for me. Details see code comments!

Checklist

• confirm this fixes things on Linux -> adjourned to when we have a new dev release
• confirm this doesn't cause new issues on Windows
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