Compose Networks - macvlan

I know this is relatively brand new, but I’m trying to understand how to create/specify macvlan networks in a compose file. Currently I’ve made some attempts to mimic the IPAM config section, but have continued to run into errors and when there are no errors, I’m not seeming to get the container on the correct network. For now I’ve resorted to creating the network externally and specifying the external network. Would be great if there was documentation to using macvlan in the compose file.