curl --request PUT \
  --url https://api.ngrok.com/edges/tls/{id}/backend \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --header 'ngrok-version: <ngrok-version>' \
  --data '
{
  "id": "<string>",
  "module": {
    "enabled": true,
    "backend_id": "<string>"
  }
}
'

{
  "enabled": true,
  "backend": {
    "id": "<string>",
    "uri": "<string>"
  }
}