curl --request PUT \
  --url https://api.hubapi.com/content/api/v2/templates/{template_id}/buffer \
  --header 'Content-Type: application/json' \
  --data '{
  "source": "<string>"
}'

{
  "id": "<string>",
  "label": "<string>",
  "path": "<string>",
  "source": "<string>",
  "category_id": 123,
  "template_type": "<string>",
  "folder": "<string>",
  "is_available_for_new_content": true,
  "is_from_layout": true,
  "is_read_only": true,
  "cdn_url": "<string>",
  "cdn_minified_url": "<string>",
  "deleted_at": 123,
  "generated_from_layout_id": "<string>",
  "thumbnail_path": "<string>",
  "thumbnail_width": 123,
  "updated": 123,
  "updated_by": "<string>",
  "portal_id": 123,
  "archived": true,
  "linked_style_id": "<string>",
  "type": "<string>"
}