Define port for plumber in RStudio IDE preview

I'm using the plumber support built into the preview version of RStudio IDE. It's great btw!

One question: can I fix the port it uses when running locally? By default it's picked randomly for each IDE session. I've another client app calling the API - which means I need to update the port in the client each time. It's not a major hassle, given I'm developing both on the same machine. It would just be easier to fix the port in both.