Function with_spinner 

async fn with_spinner<F, T>(label: &str, msg_prefix: &str, fut: F) -> T
where
    F: Future<Output = T>,

Run fut while animating the boot spinner so the user sees the [ ⠙ ] name msg_prefix N.Ns line update steadily even when the underlying RPC takes a while (Driver(CMD_INIT) for sensor-warm-up packages routinely sits at 30+ seconds). Without this the line goes silent right after wait_for_registration finishes and rbnx looks hung between OK lines.