How do I eject an external drive that is indexed by Spotlight?

Similar to [this question](https://apple.stackexchange.com/questions/142459/how-to-eject-my-external-drive-when-my-mac-refuses-because-of-spotlight) , I have an external SSD that I use as expanded storage when my MacBook Pro is docked. I would like the contents of that disk to be searchable with Spotlight, so I have indexing enabled. The problem is that most times I try to eject that drive I'm met with the message, > The disk "External" wasn't ejected because one or more programs may be using it. I believe the culprit is mds and its related processes, but I'm not entirely sure. Is there a good way to reliably eject an external drive that has Spotlight indexing enabled?