Adding AuthOptions in the Search Service terraform

In azure you can connect to azure search service using api keys and managed identities. However, there is no way to set that in the terraform. I n my understanding the use of managed identity is still a preview feature which may have been the reason for this. I would really like to setup my service to use managed identity and since I have been managing all infra things using terraform, I would like to use terraform for this purpose as well. Is there a way to get this done using terraform? Is using terraform with arm template my only option here?