Why Raw Asynchrony Inside the Presentation Layer Breaks Separation of Concerns, User Experience, and Testability Every Flutter developer remembers the magic of their first FutureBuilder . You paste an HTTP request directly into a FutureBuilder inside your widget's build() method, configure a CircularProgressIndicator for ConnectionState.waiting , render your data in ConnectionState.done , and suddenly your app is alive with real-time data in fewer than twenty lines of code. It...