I am interested in using a chat SDK for a community mobile Flutter app. I am between SendBird and Stream. I currently have 2,000 monthly active users and plan to have close to 5,000 active users chatting on the app. Has anyone used either and had good/bad experiences? Currently, there is no chat functionality, and we would like to have a 1-to-1 user chat, group chat, and large community chat capabilities.