code: protected function processAttachments(array $attachments)
      {
          $processedAttachments = [];
          $inline = [];
          foreach ($attachments as $attachment) {
              $path = $attachment->getPath();
              $id = $attachment->getId();
              if (isset($id)) {
                  // Inline
                  $inline[] = $path;
              } else {
                  // Attached
                  $processedAttachments[$attachment->getName()] = $path;
              }
          }
  
          return [$processedAttachments, $inline];
      }
docs: @param Attachment[] $attachments
  
  @return array First element: An array of attachment paths. Second element: An array of inline paths