Add documentation and example

documentation/docs/messaging.md

@@ -1,16 +1,20 @@
 # Messaging
 
-There are 2 types of special comments that you can mark messages with.
+There are special comments that you can mark messages with.
 
-## 📢 Rust Signal
+## 📢 Channels
 
-`[RINF:RUST-SIGNAL]` generates a channel from Rust to Dart.
+`[RINF:RUST-SIGNAL]` generates a message channel from Rust to Dart.
 
 ```proto title="Protobuf"
 // [RINF:RUST-SIGNAL]
 message MyDataOutput { ... }
 ```
 
+```rust title="Rust"
+MyDataOutput { ... }.send_signal_to_dart();
+```
+
 ```dart title="Dart"
 StreamBuilder(
   stream: MyDataOutput.rustSignalStream,
@@ -25,17 +29,18 @@ StreamBuilder(
 )
 ```
 
-```rust title="Rust"
-MyDataOutput { ... }.send_signal_to_dart();
-```
-
 Use `[RINF:RUST-SIGNAL-BINARY]` to include binary data without the overhead of serialization.
 
 ```proto title="Protobuf"
 // [RINF:RUST-SIGNAL-BINARY]
 message MyDataOutput { ... }
 ```
 
+```rust title="Rust"
+let binary: Vec<u8> = vec![0; 64];
+MyDataOutput { ... }.send_signal_to_dart(binary);
+```
+
 ```dart title="Dart"
 StreamBuilder(
   stream: MyDataOutput.rustSignalStream,
@@ -51,14 +56,7 @@ StreamBuilder(
 )
 ```
 
-```rust title="Rust"
-let binary: Vec<u8> = vec![0; 64];
-MyDataOutput { ... }.send_signal_to_dart(binary);
-```
-
-## 📭 Dart Signal
-
-`[RINF:DART-SIGNAL]` generates a channel from Dart to Rust.
+`[RINF:DART-SIGNAL]` generates a message channel from Dart to Rust.
 
 ```proto title="Protobuf"
 // [RINF:DART-SIGNAL]
@@ -97,3 +95,12 @@ while let Some(dart_signal) = receiver.recv().await {
     // Custom Rust logic here
 }
 ```
+
+## 🔖 Attributes
+
+`[RINF:RUST-ATTRIBUTE(...)]` writes an attribute above the generated message struct in Rust. This is useful when you want to automatically implement a trait for the message struct in Rust.
+
+```proto title="Protobuf"
+// [RINF:RUST-ATTRIBUTE(#[derive(Copy)])]
+message MyDataInput { ... }
+```

flutter_ffi_plugin/example/messages/sample_folder/enum_and_oneof.proto → flutter_ffi_plugin/example/messages/sample_folder/sample_file.proto

@@ -1,5 +1,5 @@
 syntax = "proto3";
-package enum_and_oneof;
+package sample_file;
 
 enum Kind {
   one = 0;
@@ -23,3 +23,8 @@ message SampleOutput {
     int32 age = 3;
   }
 }
+
+// [RINF:RUST-ATTRIBUTE(#[derive(Copy)])]
+message WithRustAttribute {
+  bool dummy = 1;
+}

flutter_ffi_plugin/example/native/hub/src/sample_functions.rs

@@ -109,7 +109,7 @@ pub async fn stream_fractal() {
 // A dummy function that uses sample messages to eliminate warnings.
 #[allow(dead_code)]
 async fn use_messages() -> Result<()> {
-    use messages::sample_folder::enum_and_oneof::*;
+    use messages::sample_folder::sample_file::*;
     let _ = SampleInput::get_dart_signal_receiver()?;
     SampleOutput {
         kind: 3,