It's safe to send "START SLAVE SQL_THREAD" unconditionally when the timeout is reached, as innobackupex runs START/STOP SLAVE SQL_THREAD in a loop in wait_for_safe_slave before the timeout anyway.
It's safe to send "START SLAVE SQL_THREAD" unconditionally when the timeout is reached, as innobackupex runs START/STOP SLAVE SQL_THREAD in a loop in wait_for_safe_slave before the timeout anyway.