Stack Traces
This is standard Rust behavior, and is unrelated to flutter_rust_bridge. However, we do provide defaults to be "battery included".
If using the template by flutter_rust_bridge_codegen create/integrate, this is already configured by default,
via the auto-generated call to flutter_rust_bridge::setup_default_user_utils().
Errors (Result)
To pass Rust stack traces to flutter, you need to set RUST_BACKTRACE in the running application. For that simply add env::set_var("RUST_BACKTRACE", "1"); before initialising the bridge.
Note: The --dart-define will not work, you must use env::set_var, because the former does not set the "environment variable" in the common sense, but instead a special thing only visible to Dart.
Panics
The standard Rust does not provide stack traces when catching a panic. If you want to know the stack traces, you can use approaches like https://stackoverflow.com/questions/69593235/how-to-get-panic-information-i-e-stack-trace-with-catch-unwind. The builtin utils do use it.
Other solutions
There are many products to help you capture errors and provide a central panel to look at them. This official Flutter page lists some of them: Bugsnag, Datadog, Firebase Crashlytics, Rollbar, or Sentry. This will be especially useful for your app in production.
Behavior on Windows
It seems that Rust+Windows(+Flutter) does not handle stack traces well, which is not a bug of flutter_rust_bridge, but something on upstream.
The current discussions and workarounds are in https://github.com/fzyzcjy/flutter_rust_bridge/issues/2200.