@pragma('vm:entry-point') requirement for isolate entry points

[alnitak]

Regarding flutter-handling-concurrency skill.

When spawning an isolate using Isolate.spawn(), the entry point callback function is invoked dynamically by the Dart VM. Unlike regular function calls that the compiler can track through static analysis, the VM looks up this function at runtime to start the isolate's execution.

Solution
Add the @pragma('vm:entry-point') annotation to all isolate entry point functions. This annotation explicitly tells the Dart compiler that the function is an entry point that will be invoked by the VM, preventing it from being tree-shaken.