code: public function getVclSnippets($path = '/vcl_snippets', $specificFile = null)
      {
          $snippetsData = [];
  
          $moduleEtcPath = $this->reader->getModuleDir(Dir::MODULE_ETC_DIR, 'Fastly_Cdn') . $path;
          $directoryRead = $this->readFactory->create($moduleEtcPath);
          if (!$specificFile) {
              $files = $directoryRead->read();
  
              if (is_array($files)) {
                  foreach ($files as $file) {
                      if (substr($file, strpos($file, ".") + 1) !== 'vcl') {
                          continue;
                      }
                      $snippetFilePath = $moduleEtcPath . '/' . $file;
                      $snippetFilePath = $directoryRead->getRelativePath($snippetFilePath);
                      $type = explode('.', $file)[0];
                      $snippetsData[$type] = $directoryRead->readFile($snippetFilePath);
                  }
              }
          } else {
              $snippetFilePath = $moduleEtcPath . '/' . $specificFile;
              $snippetFilePath = $directoryRead->getRelativePath($snippetFilePath);
              $type = explode('.', $specificFile)[0];
              $snippetsData[$type] = $directoryRead->readFile($snippetFilePath);
          }
  
          return $snippetsData;
      }
docs: Returns VCL snippet data
  
  @param string $path
  @param null $specificFile
  @return array
  @throws \Magento\Framework\Exception\FileSystemException