multicore_lockout_end_timeout_us() function

true if the other core successfully exited locked out state within the timeout, false otherwise

be very careful using small timeout values, as a timeout here will leave the "lockout" functionality in a bad state. It is probably preferable to use multicore_lockout_end_blocking anyway as if you have already waited for the victim core to enter the lockout state, then the victim core will be ready to exit the lockout state very quickly.