code: private function clearExpiredCacheEntries(int $now)
      {
          $this->now = $now;
  
          foreach ($this->cacheTimeouts as $path => $timeout) {
              if ($now <= $timeout) {
                  break;
              }
  
              $fileInfo = $this->cache[$path];
  
              unset(
                  $this->cache[$path],
                  $this->cacheTimeouts[$path]
              );
  
              $this->bufferedFileCount -= isset($fileInfo->buffer);
              $this->cacheEntryCount--;
          }
      }
docs: Removes expired file information from the cache and updates the current 'now' value.
  
  @param int $now