how to use this sidecar method?

[Shuanbao-Liu]

Hello,I meet a question: I use the command :kubectl edit cm xxx, then use the Vi to modify the file, after edit ,how to use this sidecar to update the configmaps ?

Usage of ./out/configmap-reload:

-volume-dir value

the config map volume directory to watch for updates; may be used multiple times

I can not understand the usage ,could you help me give us a specific example?

Thanks a lot and have a nice day .
All wishes:)