in gke-windows-builder/builder/builder/network.go [59:66]
func usingSharedVPC(netConfig *InstanceNetworkConfig, instanceProject *string) bool {
if *netConfig.NetworkProject != "" && *netConfig.NetworkProject != *instanceProject {
// If --network-project was set and is different than the instance project
// this indicates that the user is using a Shared VPC
return true
}
return false
}