This module allows discovering the addresses reserved in subnets when [DNS Inbound Policies](https://cloud.google.com/dns/docs/policies) are configured.
Since it's currently impossible to fetch those addresses using a GCP data source (see [this issue](https://github.com/hashicorp/terraform-provider-google/issues/3753) for more details), the workaround used here is to derive the authorization token from the Google provider, and do a direct HTTP call to the Compute API.