install_id spawns reg query for MachineGuid. The shipped image is a
GUI-subsystem binary and owns no console, so Windows allocated one and a black
box flashed at every startup. CREATE_NO_WINDOW suppresses it, through
std::os::windows::process::CommandExt, with no new dependency.
The command, its arguments, its stdout and its parse are untouched. That
matters: this value is a KDF input, and .output() captures the same bytes --
only the console attachment changes.
cc
vicrodh
cb2a61cbd9