attemptMemoryReclaim example

$this->message->display(
        $this->t(
          'Memory usage is @usage (@pct% of limit @limit), reclaiming memory.',
          [
            '@pct' => round($pct_memory * 100),
            '@usage' => $this->formatSize($usage),
            '@limit' => $this->formatSize($this->memoryLimit),
          ]
        ),
        'warning'
      );
      $usage = $this->attemptMemoryReclaim();
      $pct_memory = $usage / $this->memoryLimit;
      // Use a lower threshold - we don't want to be in a situation where we keep       // coming back here and trimming a tiny amount       if ($pct_memory > (0.90 * $threshold)) {
        $this->message->display(
          $this->t(
            'Memory usage is now @usage (@pct% of limit @limit), not enough reclaimed, starting new batch',
            [
              '@pct' => round($pct_memory * 100),
              '@usage' => $this->formatSize($usage),
              '@limit' => $this->formatSize($this->memoryLimit),
            ]