code: @InternalApi
    public com.google.bigtable.admin.v2.CreateClusterRequest toProto(String projectId) {
      proto.setParent(NameUtil.formatInstanceName(projectId, instanceId));
      proto.getClusterBuilder().setLocation(NameUtil.formatLocationName(projectId, zone));
  
      return proto.build();
    }
docs: Creates the request protobuf. This method is considered an internal implementation detail and
  not meant to be used by applications.