How does one create a multi-architecture Docker Engine Plugin?

This questions is specifically about Docker Engine managed plugin system plugins, such as volume or network drivers.

As per the instructions in the link above:

A new plugin can be created by running docker plugin create <plugin-name> ./path/to/plugin/data where the plugin data contains a plugin configuration file config.json and a root filesystem in subdirectory rootfs.
After that the plugin <plugin-name> will show up in docker plugin ls . Plugins can be pushed to remote registries with docker plugin push <plugin-name> .

How, then, can the plugin be made for multiple architectures(amd64/arm64/others)? The root file system can have binaries for only one architecture after all.