protected function storeLastRun()
    {
        // Silence warnings, which might be caused by multiple possible
        // failures. We handle and log them anyways.
        if ( !@file_put_contents( $this->lockDir . '/lastRun', time() ) )
        {
            $this->logger->log(
                'Failure storing last run time: ' . ( isset( $php_errormsg ) ? $php_errormsg : 'Unknown error - enable the track_errors ini directive.' ),
                Logger::ERROR
            );
            return;
        }

        $this->logger->log( 'Stored last run time.', Logger::INFO );
    }