Why Redis Service?

in the bot kit Config.json file, there is a section for Redis details, why is that required?
is it required to be configured for Agent Transfer?

{ "server": { "port": 8003 }, "app": { "apiPrefix" : "", "url": "" }, "credentials": { "apikey": "", "appId": "7", "st-67890":{ "apikey": "", "appId": "" } }, "redis": { "options": { "host": "localhost", "port": 6379 }, "available": false }, "examples" : { "mockServicesHost" : "http://localhost:8004" }, "liveagentlicense": "", "supportsMessageAck": true, "languages":["en","de"] }

Please read through this and you will get some idea.