Function running_under_wsl2 

pub fn running_under_wsl2() -> bool

true when running inside WSL2 (a real Linux kernel on Hyper-V).

Under WSL2:

• ZNS/CSD commands are rejected by the Hyper-V storage emulation.
• Port 4242 is behind NAT by default. Enable Mirrored Mode in ~/.wslconfig:

  [wsl2]
  networkingMode=mirrored