Getting to Slack faster with incremental boot

This post details the implementation of an incremental boot process for Slack's web application. This process involves fetching only the data required for the initial channel view, making content visible much faster. It also describes the parallel fetching of the full model data via `rtm.start` and the subsequent re-enabling of the UI once all data is processed. This approach resulted in a significant reduction in 'content visible' time (from ~7s to <5s) and a smaller reduction in 'fully loaded' time (from ~7s to ~6s), saving users substantial waiting time daily.