feat(poc/bridge): add flutter_rust_bridge hello spike

Proof-of-concept proving the Flutter/Rust bridge exit criterion from
docs/architecture/proof-of-concept-plan.md §2:
  "Flutter can call Rust and receive event stream data."

The spike exposes one synchronous fallible command (greet) returning
a typed GreetResult / GreetError DTO, and one async event stream
(counter_stream) emitting typed CounterTick events. The Flutter app
demonstrates both flows on a Material 3 surface; the headless test
suite in test/poc_verification_test.dart exercises the same API
directly through dart:ffi.

Verified on 2026-05-13 (Linux desktop, Flutter 3.41.9 / Dart 3.11.5,
flutter_rust_bridge 2.12.0, Rust 1.95). All three tests pass:
  - greet() returns typed result for valid input
  - greet() surfaces typed error for empty input
  - counterStream() delivers the expected event sequence

Authority: PoC plan §2, DEC-014 (typed Flutter/Rust bridge),
SAD-068, SDD-079, SysDes-049.
Naming note: the PoC plan lists this as flutter-rust-bridge-hello,
but Dart pubspec.yaml package names require underscores; the
directory uses underscores accordingly.
Not product code; not promoted into chanora_bridge.

Layout note: includes the full Flutter platform scaffold (android,
ios, macos, windows, web, linux). Only the Linux desktop target has
been built and verified.

poc/flutter_rust_bridge_hello/rust/src/api/mod.rs

@@ -0,0 +1 @@
+pub mod simple;

poc/flutter_rust_bridge_hello/rust/src/api/simple.rs

@@ -0,0 +1,97 @@
+//! Chanora PoC API — `flutter_rust_bridge_hello`.
+//!
+//! Two flows are proven here:
+//!   1. **Command:** `greet` — typed input → typed `Result<T, E>` DTO,
+//!      including typed error mapping at the boundary.
+//!   2. **Event stream:** `counterStream` — Rust pushes typed events to
+//!      Dart via a `StreamSink`, observed in Dart as a `Stream<CounterTick>`.
+//!
+//! Together they satisfy the PoC exit criterion from
+//! `docs/architecture/proof-of-concept-plan.md` §2:
+//!     "Flutter can call Rust and receive event stream data."
+//!
+//! This is PoC code only. The Chanora DTO catalogue belongs to the
+//! `chanora_bridge` crate; this PoC does not stand in for it.
+
+use std::time::Duration;
+
+use flutter_rust_bridge::frb;
+
+use crate::frb_generated::StreamSink;
+
+// -------- Command DTOs --------
+
+#[derive(Debug, Clone)]
+pub struct GreetResult {
+    pub message: String,
+    pub elapsed_micros: u64,
+}
+
+#[derive(Debug, Clone)]
+pub enum GreetErrorKind {
+    EmptyName,
+}
+
+/// Typed error DTO surfaced as a Dart exception by FRB.
+#[derive(Debug, Clone, thiserror::Error)]
+#[error("greet error: {kind:?}: {detail}")]
+pub struct GreetError {
+    pub kind: GreetErrorKind,
+    pub detail: String,
+}
+
+// -------- Lifecycle --------
+
+#[frb(init)]
+pub fn init_app() {
+    flutter_rust_bridge::setup_default_user_utils();
+}
+
+// -------- Command --------
+
+/// Synchronous fallible command. Proves Dart → Rust call with a typed
+/// `Result` DTO crossing the boundary.
+#[frb(sync)]
+pub fn greet(name: String) -> Result<GreetResult, GreetError> {
+    let start = std::time::Instant::now();
+    let trimmed = name.trim();
+    if trimmed.is_empty() {
+        return Err(GreetError {
+            kind: GreetErrorKind::EmptyName,
+            detail: "name must not be empty".into(),
+        });
+    }
+    Ok(GreetResult {
+        message: format!("Hello, {trimmed}! — greetings from Rust."),
+        elapsed_micros: start.elapsed().as_micros() as u64,
+    })
+}
+
+// -------- Event stream --------
+
+#[derive(Debug, Clone)]
+pub struct CounterTick {
+    pub seq: u64,
+    pub note: String,
+}
+
+/// Rust → Dart event stream.
+/// `StreamSink` is provided in scope by `flutter_rust_bridge` glue;
+/// the codegen wires it to a Dart `Stream<CounterTick>`.
+pub async fn counter_stream(
+    sink: StreamSink<CounterTick>,
+    count: u32,
+    interval_ms: u32,
+) {
+    let interval = Duration::from_millis(interval_ms.max(1) as u64);
+    for i in 0..count {
+        let tick = CounterTick {
+            seq: i as u64,
+            note: format!("tick {i}/{count}"),
+        };
+        if sink.add(tick).is_err() {
+            break;
+        }
+        tokio::time::sleep(interval).await;
+    }
+}

poc/flutter_rust_bridge_hello/rust/src/frb_generated.rs

@@ -0,0 +1,558 @@
+// This file is automatically generated, so please do not edit it.
+// @generated by `flutter_rust_bridge`@ 2.12.0.
+
+#![allow(
+    non_camel_case_types,
+    unused,
+    non_snake_case,
+    clippy::needless_return,
+    clippy::redundant_closure_call,
+    clippy::redundant_closure,
+    clippy::useless_conversion,
+    clippy::unit_arg,
+    clippy::unused_unit,
+    clippy::double_parens,
+    clippy::let_and_return,
+    clippy::too_many_arguments,
+    clippy::match_single_binding,
+    clippy::clone_on_copy,
+    clippy::let_unit_value,
+    clippy::deref_addrof,
+    clippy::explicit_auto_deref,
+    clippy::borrow_deref_ref,
+    clippy::uninlined_format_args,
+    clippy::needless_borrow
+)]
+
+// Section: imports
+
+use flutter_rust_bridge::for_generated::byteorder::{NativeEndian, ReadBytesExt, WriteBytesExt};
+use flutter_rust_bridge::for_generated::{transform_result_dco, Lifetimeable, Lockable};
+use flutter_rust_bridge::{Handler, IntoIntoDart};
+
+// Section: boilerplate
+
+flutter_rust_bridge::frb_generated_boilerplate!(
+    default_stream_sink_codec = SseCodec,
+    default_rust_opaque = RustOpaqueMoi,
+    default_rust_auto_opaque = RustAutoOpaqueMoi,
+);
+pub(crate) const FLUTTER_RUST_BRIDGE_CODEGEN_VERSION: &str = "2.12.0";
+pub(crate) const FLUTTER_RUST_BRIDGE_CODEGEN_CONTENT_HASH: i32 = -1685941124;
+
+// Section: executor
+
+flutter_rust_bridge::frb_generated_default_handler!();
+
+// Section: wire_funcs
+
+fn wire__crate__api__simple__counter_stream_impl(
+    port_: flutter_rust_bridge::for_generated::MessagePort,
+    ptr_: flutter_rust_bridge::for_generated::PlatformGeneralizedUint8ListPtr,
+    rust_vec_len_: i32,
+    data_len_: i32,
+) {
+    FLUTTER_RUST_BRIDGE_HANDLER.wrap_async::<flutter_rust_bridge::for_generated::SseCodec, _, _, _>(
+        flutter_rust_bridge::for_generated::TaskInfo {
+            debug_name: "counter_stream",
+            port: Some(port_),
+            mode: flutter_rust_bridge::for_generated::FfiCallMode::Normal,
+        },
+        move || {
+            let message = unsafe {
+                flutter_rust_bridge::for_generated::Dart2RustMessageSse::from_wire(
+                    ptr_,
+                    rust_vec_len_,
+                    data_len_,
+                )
+            };
+            let mut deserializer =
+                flutter_rust_bridge::for_generated::SseDeserializer::new(message);
+            let api_sink = <StreamSink<
+                crate::api::simple::CounterTick,
+                flutter_rust_bridge::for_generated::SseCodec,
+            >>::sse_decode(&mut deserializer);
+            let api_count = <u32>::sse_decode(&mut deserializer);
+            let api_interval_ms = <u32>::sse_decode(&mut deserializer);
+            deserializer.end();
+            move |context| async move {
+                transform_result_sse::<_, ()>(
+                    (move || async move {
+                        let output_ok = Result::<_, ()>::Ok({
+                            crate::api::simple::counter_stream(
+                                api_sink,
+                                api_count,
+                                api_interval_ms,
+                            )
+                            .await;
+                        })?;
+                        Ok(output_ok)
+                    })()
+                    .await,
+                )
+            }
+        },
+    )
+}
+fn wire__crate__api__simple__greet_impl(
+    ptr_: flutter_rust_bridge::for_generated::PlatformGeneralizedUint8ListPtr,
+    rust_vec_len_: i32,
+    data_len_: i32,
+) -> flutter_rust_bridge::for_generated::WireSyncRust2DartSse {
+    FLUTTER_RUST_BRIDGE_HANDLER.wrap_sync::<flutter_rust_bridge::for_generated::SseCodec, _>(
+        flutter_rust_bridge::for_generated::TaskInfo {
+            debug_name: "greet",
+            port: None,
+            mode: flutter_rust_bridge::for_generated::FfiCallMode::Sync,
+        },
+        move || {
+            let message = unsafe {
+                flutter_rust_bridge::for_generated::Dart2RustMessageSse::from_wire(
+                    ptr_,
+                    rust_vec_len_,
+                    data_len_,
+                )
+            };
+            let mut deserializer =
+                flutter_rust_bridge::for_generated::SseDeserializer::new(message);
+            let api_name = <String>::sse_decode(&mut deserializer);
+            deserializer.end();
+            transform_result_sse::<_, crate::api::simple::GreetError>((move || {
+                let output_ok = crate::api::simple::greet(api_name)?;
+                Ok(output_ok)
+            })())
+        },
+    )
+}
+fn wire__crate__api__simple__init_app_impl(
+    port_: flutter_rust_bridge::for_generated::MessagePort,
+    ptr_: flutter_rust_bridge::for_generated::PlatformGeneralizedUint8ListPtr,
+    rust_vec_len_: i32,
+    data_len_: i32,
+) {
+    FLUTTER_RUST_BRIDGE_HANDLER.wrap_normal::<flutter_rust_bridge::for_generated::SseCodec, _, _>(
+        flutter_rust_bridge::for_generated::TaskInfo {
+            debug_name: "init_app",
+            port: Some(port_),
+            mode: flutter_rust_bridge::for_generated::FfiCallMode::Normal,
+        },
+        move || {
+            let message = unsafe {
+                flutter_rust_bridge::for_generated::Dart2RustMessageSse::from_wire(
+                    ptr_,
+                    rust_vec_len_,
+                    data_len_,
+                )
+            };
+            let mut deserializer =
+                flutter_rust_bridge::for_generated::SseDeserializer::new(message);
+            deserializer.end();
+            move |context| {
+                transform_result_sse::<_, ()>((move || {
+                    let output_ok = Result::<_, ()>::Ok({
+                        crate::api::simple::init_app();
+                    })?;
+                    Ok(output_ok)
+                })())
+            }
+        },
+    )
+}
+
+// Section: dart2rust
+
+impl SseDecode for flutter_rust_bridge::for_generated::anyhow::Error {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_decode(deserializer: &mut flutter_rust_bridge::for_generated::SseDeserializer) -> Self {
+        let mut inner = <String>::sse_decode(deserializer);
+        return flutter_rust_bridge::for_generated::anyhow::anyhow!("{}", inner);
+    }
+}
+
+impl SseDecode
+    for StreamSink<crate::api::simple::CounterTick, flutter_rust_bridge::for_generated::SseCodec>
+{
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_decode(deserializer: &mut flutter_rust_bridge::for_generated::SseDeserializer) -> Self {
+        let mut inner = <String>::sse_decode(deserializer);
+        return StreamSink::deserialize(inner);
+    }
+}
+
+impl SseDecode for String {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_decode(deserializer: &mut flutter_rust_bridge::for_generated::SseDeserializer) -> Self {
+        let mut inner = <Vec<u8>>::sse_decode(deserializer);
+        return String::from_utf8(inner).unwrap();
+    }
+}
+
+impl SseDecode for crate::api::simple::CounterTick {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_decode(deserializer: &mut flutter_rust_bridge::for_generated::SseDeserializer) -> Self {
+        let mut var_seq = <u64>::sse_decode(deserializer);
+        let mut var_note = <String>::sse_decode(deserializer);
+        return crate::api::simple::CounterTick {
+            seq: var_seq,
+            note: var_note,
+        };
+    }
+}
+
+impl SseDecode for crate::api::simple::GreetError {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_decode(deserializer: &mut flutter_rust_bridge::for_generated::SseDeserializer) -> Self {
+        let mut var_kind = <crate::api::simple::GreetErrorKind>::sse_decode(deserializer);
+        let mut var_detail = <String>::sse_decode(deserializer);
+        return crate::api::simple::GreetError {
+            kind: var_kind,
+            detail: var_detail,
+        };
+    }
+}
+
+impl SseDecode for crate::api::simple::GreetErrorKind {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_decode(deserializer: &mut flutter_rust_bridge::for_generated::SseDeserializer) -> Self {
+        let mut inner = <i32>::sse_decode(deserializer);
+        return match inner {
+            0 => crate::api::simple::GreetErrorKind::EmptyName,
+            _ => unreachable!("Invalid variant for GreetErrorKind: {}", inner),
+        };
+    }
+}
+
+impl SseDecode for crate::api::simple::GreetResult {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_decode(deserializer: &mut flutter_rust_bridge::for_generated::SseDeserializer) -> Self {
+        let mut var_message = <String>::sse_decode(deserializer);
+        let mut var_elapsedMicros = <u64>::sse_decode(deserializer);
+        return crate::api::simple::GreetResult {
+            message: var_message,
+            elapsed_micros: var_elapsedMicros,
+        };
+    }
+}
+
+impl SseDecode for i32 {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_decode(deserializer: &mut flutter_rust_bridge::for_generated::SseDeserializer) -> Self {
+        deserializer.cursor.read_i32::<NativeEndian>().unwrap()
+    }
+}
+
+impl SseDecode for Vec<u8> {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_decode(deserializer: &mut flutter_rust_bridge::for_generated::SseDeserializer) -> Self {
+        let mut len_ = <i32>::sse_decode(deserializer);
+        let mut ans_ = Vec::with_capacity(len_ as usize);
+        for idx_ in 0..len_ {
+            ans_.push(<u8>::sse_decode(deserializer));
+        }
+        return ans_;
+    }
+}
+
+impl SseDecode for u32 {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_decode(deserializer: &mut flutter_rust_bridge::for_generated::SseDeserializer) -> Self {
+        deserializer.cursor.read_u32::<NativeEndian>().unwrap()
+    }
+}
+
+impl SseDecode for u64 {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_decode(deserializer: &mut flutter_rust_bridge::for_generated::SseDeserializer) -> Self {
+        deserializer.cursor.read_u64::<NativeEndian>().unwrap()
+    }
+}
+
+impl SseDecode for u8 {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_decode(deserializer: &mut flutter_rust_bridge::for_generated::SseDeserializer) -> Self {
+        deserializer.cursor.read_u8().unwrap()
+    }
+}
+
+impl SseDecode for () {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_decode(deserializer: &mut flutter_rust_bridge::for_generated::SseDeserializer) -> Self {}
+}
+
+impl SseDecode for bool {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_decode(deserializer: &mut flutter_rust_bridge::for_generated::SseDeserializer) -> Self {
+        deserializer.cursor.read_u8().unwrap() != 0
+    }
+}
+
+fn pde_ffi_dispatcher_primary_impl(
+    func_id: i32,
+    port: flutter_rust_bridge::for_generated::MessagePort,
+    ptr: flutter_rust_bridge::for_generated::PlatformGeneralizedUint8ListPtr,
+    rust_vec_len: i32,
+    data_len: i32,
+) {
+    // Codec=Pde (Serialization + dispatch), see doc to use other codecs
+    match func_id {
+        1 => wire__crate__api__simple__counter_stream_impl(port, ptr, rust_vec_len, data_len),
+        3 => wire__crate__api__simple__init_app_impl(port, ptr, rust_vec_len, data_len),
+        _ => unreachable!(),
+    }
+}
+
+fn pde_ffi_dispatcher_sync_impl(
+    func_id: i32,
+    ptr: flutter_rust_bridge::for_generated::PlatformGeneralizedUint8ListPtr,
+    rust_vec_len: i32,
+    data_len: i32,
+) -> flutter_rust_bridge::for_generated::WireSyncRust2DartSse {
+    // Codec=Pde (Serialization + dispatch), see doc to use other codecs
+    match func_id {
+        2 => wire__crate__api__simple__greet_impl(ptr, rust_vec_len, data_len),
+        _ => unreachable!(),
+    }
+}
+
+// Section: rust2dart
+
+// Codec=Dco (DartCObject based), see doc to use other codecs
+impl flutter_rust_bridge::IntoDart for crate::api::simple::CounterTick {
+    fn into_dart(self) -> flutter_rust_bridge::for_generated::DartAbi {
+        [
+            self.seq.into_into_dart().into_dart(),
+            self.note.into_into_dart().into_dart(),
+        ]
+        .into_dart()
+    }
+}
+impl flutter_rust_bridge::for_generated::IntoDartExceptPrimitive
+    for crate::api::simple::CounterTick
+{
+}
+impl flutter_rust_bridge::IntoIntoDart<crate::api::simple::CounterTick>
+    for crate::api::simple::CounterTick
+{
+    fn into_into_dart(self) -> crate::api::simple::CounterTick {
+        self
+    }
+}
+// Codec=Dco (DartCObject based), see doc to use other codecs
+impl flutter_rust_bridge::IntoDart for crate::api::simple::GreetError {
+    fn into_dart(self) -> flutter_rust_bridge::for_generated::DartAbi {
+        [
+            self.kind.into_into_dart().into_dart(),
+            self.detail.into_into_dart().into_dart(),
+        ]
+        .into_dart()
+    }
+}
+impl flutter_rust_bridge::for_generated::IntoDartExceptPrimitive
+    for crate::api::simple::GreetError
+{
+}
+impl flutter_rust_bridge::IntoIntoDart<crate::api::simple::GreetError>
+    for crate::api::simple::GreetError
+{
+    fn into_into_dart(self) -> crate::api::simple::GreetError {
+        self
+    }
+}
+// Codec=Dco (DartCObject based), see doc to use other codecs
+impl flutter_rust_bridge::IntoDart for crate::api::simple::GreetErrorKind {
+    fn into_dart(self) -> flutter_rust_bridge::for_generated::DartAbi {
+        match self {
+            Self::EmptyName => 0.into_dart(),
+            _ => unreachable!(),
+        }
+    }
+}
+impl flutter_rust_bridge::for_generated::IntoDartExceptPrimitive
+    for crate::api::simple::GreetErrorKind
+{
+}
+impl flutter_rust_bridge::IntoIntoDart<crate::api::simple::GreetErrorKind>
+    for crate::api::simple::GreetErrorKind
+{
+    fn into_into_dart(self) -> crate::api::simple::GreetErrorKind {
+        self
+    }
+}
+// Codec=Dco (DartCObject based), see doc to use other codecs
+impl flutter_rust_bridge::IntoDart for crate::api::simple::GreetResult {
+    fn into_dart(self) -> flutter_rust_bridge::for_generated::DartAbi {
+        [
+            self.message.into_into_dart().into_dart(),
+            self.elapsed_micros.into_into_dart().into_dart(),
+        ]
+        .into_dart()
+    }
+}
+impl flutter_rust_bridge::for_generated::IntoDartExceptPrimitive
+    for crate::api::simple::GreetResult
+{
+}
+impl flutter_rust_bridge::IntoIntoDart<crate::api::simple::GreetResult>
+    for crate::api::simple::GreetResult
+{
+    fn into_into_dart(self) -> crate::api::simple::GreetResult {
+        self
+    }
+}
+
+impl SseEncode for flutter_rust_bridge::for_generated::anyhow::Error {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_encode(self, serializer: &mut flutter_rust_bridge::for_generated::SseSerializer) {
+        <String>::sse_encode(format!("{:?}", self), serializer);
+    }
+}
+
+impl SseEncode
+    for StreamSink<crate::api::simple::CounterTick, flutter_rust_bridge::for_generated::SseCodec>
+{
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_encode(self, serializer: &mut flutter_rust_bridge::for_generated::SseSerializer) {
+        unimplemented!("")
+    }
+}
+
+impl SseEncode for String {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_encode(self, serializer: &mut flutter_rust_bridge::for_generated::SseSerializer) {
+        <Vec<u8>>::sse_encode(self.into_bytes(), serializer);
+    }
+}
+
+impl SseEncode for crate::api::simple::CounterTick {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_encode(self, serializer: &mut flutter_rust_bridge::for_generated::SseSerializer) {
+        <u64>::sse_encode(self.seq, serializer);
+        <String>::sse_encode(self.note, serializer);
+    }
+}
+
+impl SseEncode for crate::api::simple::GreetError {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_encode(self, serializer: &mut flutter_rust_bridge::for_generated::SseSerializer) {
+        <crate::api::simple::GreetErrorKind>::sse_encode(self.kind, serializer);
+        <String>::sse_encode(self.detail, serializer);
+    }
+}
+
+impl SseEncode for crate::api::simple::GreetErrorKind {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_encode(self, serializer: &mut flutter_rust_bridge::for_generated::SseSerializer) {
+        <i32>::sse_encode(
+            match self {
+                crate::api::simple::GreetErrorKind::EmptyName => 0,
+                _ => {
+                    unimplemented!("");
+                }
+            },
+            serializer,
+        );
+    }
+}
+
+impl SseEncode for crate::api::simple::GreetResult {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_encode(self, serializer: &mut flutter_rust_bridge::for_generated::SseSerializer) {
+        <String>::sse_encode(self.message, serializer);
+        <u64>::sse_encode(self.elapsed_micros, serializer);
+    }
+}
+
+impl SseEncode for i32 {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_encode(self, serializer: &mut flutter_rust_bridge::for_generated::SseSerializer) {
+        serializer.cursor.write_i32::<NativeEndian>(self).unwrap();
+    }
+}
+
+impl SseEncode for Vec<u8> {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_encode(self, serializer: &mut flutter_rust_bridge::for_generated::SseSerializer) {
+        <i32>::sse_encode(self.len() as _, serializer);
+        for item in self {
+            <u8>::sse_encode(item, serializer);
+        }
+    }
+}
+
+impl SseEncode for u32 {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_encode(self, serializer: &mut flutter_rust_bridge::for_generated::SseSerializer) {
+        serializer.cursor.write_u32::<NativeEndian>(self).unwrap();
+    }
+}
+
+impl SseEncode for u64 {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_encode(self, serializer: &mut flutter_rust_bridge::for_generated::SseSerializer) {
+        serializer.cursor.write_u64::<NativeEndian>(self).unwrap();
+    }
+}
+
+impl SseEncode for u8 {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_encode(self, serializer: &mut flutter_rust_bridge::for_generated::SseSerializer) {
+        serializer.cursor.write_u8(self).unwrap();
+    }
+}
+
+impl SseEncode for () {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_encode(self, serializer: &mut flutter_rust_bridge::for_generated::SseSerializer) {}
+}
+
+impl SseEncode for bool {
+    // Codec=Sse (Serialization based), see doc to use other codecs
+    fn sse_encode(self, serializer: &mut flutter_rust_bridge::for_generated::SseSerializer) {
+        serializer.cursor.write_u8(self as _).unwrap();
+    }
+}
+
+#[cfg(not(target_family = "wasm"))]
+mod io {
+    // This file is automatically generated, so please do not edit it.
+    // @generated by `flutter_rust_bridge`@ 2.12.0.
+
+    // Section: imports
+
+    use super::*;
+    use flutter_rust_bridge::for_generated::byteorder::{
+        NativeEndian, ReadBytesExt, WriteBytesExt,
+    };
+    use flutter_rust_bridge::for_generated::{transform_result_dco, Lifetimeable, Lockable};
+    use flutter_rust_bridge::{Handler, IntoIntoDart};
+
+    // Section: boilerplate
+
+    flutter_rust_bridge::frb_generated_boilerplate_io!();
+}
+#[cfg(not(target_family = "wasm"))]
+pub use io::*;
+
+/// cbindgen:ignore
+#[cfg(target_family = "wasm")]
+mod web {
+    // This file is automatically generated, so please do not edit it.
+    // @generated by `flutter_rust_bridge`@ 2.12.0.
+
+    // Section: imports
+
+    use super::*;
+    use flutter_rust_bridge::for_generated::byteorder::{
+        NativeEndian, ReadBytesExt, WriteBytesExt,
+    };
+    use flutter_rust_bridge::for_generated::wasm_bindgen;
+    use flutter_rust_bridge::for_generated::wasm_bindgen::prelude::*;
+    use flutter_rust_bridge::for_generated::{transform_result_dco, Lifetimeable, Lockable};
+    use flutter_rust_bridge::{Handler, IntoIntoDart};
+
+    // Section: boilerplate
+
+    flutter_rust_bridge::frb_generated_boilerplate_web!();
+}
+#[cfg(target_family = "wasm")]
+pub use web::*;

poc/flutter_rust_bridge_hello/rust/src/lib.rs

@@ -0,0 +1,2 @@
+pub mod api;
+mod frb_generated;