getIdTokenMiddleware With External Account

[jeh5256]

I have an AWS instance that needs to authenticate with a GCP instance using Workload Identity Federation. I see in the docs it says to use the getIdTokenMiddleware method on ApplicationDefaultCredentials class. The problem I am facing is that my clientLibrary.json file has a type of "external_account" and getIdTokenMiddleware throws InvalidArgumentException.

Is there support for generating id token middleware with an external account build it or is that functionality missing? Any help, even if it means pointing me elsewhere, would be much appreciated.

Thanks!