Add comment about and guard against server-side cache usage
Add comment about and guard against server-side cache usage

Want to be extra sure that we don't accidentally cache data across requests on
the server.

emecell/react-server,redfin/react-server,lidawang/react-server,emecell/react-server,doug-wade/react-server,davidalber/react-server,lidawang/react-server,redfin/react-server,davidalber/react-server,doug-wade/react-server,szhou8813/react-server,szhou8813/react-server