Cron_Runner::start_import()

	public function start_import() {
		$lock = new Lock();
		if ( $lock->get_lock() ) {
			return; // another process has claimed it
		}

		$status  = new Status();
		$current = $status->current_status();
		if ( $current[ 'status' ] !== Status::NOT_STARTED ) {
			return; // it's already running
		}

		$lock->set_lock();
		do_action( 'bigcommerce/import/start' );
		$this->schedule_next();
		$lock->release_lock();
	}