Function install_guard_when_free 

pub fn install_guard_when_free() -> Result<SignalGuard>

What: Install the signal guard, waiting while another thread of this process holds it. Why: One wrapper process runs one Git child at a time, so the wait never happens there; library tests run several preparations in threads of one process, and the guard is process-wide.

In TS you’d write (pseudocode):

const guard = installSignalGuard();