Expose Rust executor's async runtime for customization

frb_example/integrate_third_party/rust/src/api/override_web_audio_api.rs

@@ -1,7 +1,8 @@
 use crate::api::media_element::MyMediaElement;
+use crate::frb_generated::FLUTTER_RUST_BRIDGE_HANDLER;
 use extend::ext;
 use flutter_rust_bridge::for_generated::anyhow;
-use flutter_rust_bridge::{frb, DartFnFuture};
+use flutter_rust_bridge::{frb, BaseAsyncRuntime, DartFnFuture};
 use std::sync::Arc;
 use web_audio_api::context::{AudioContext, BaseAudioContext, OfflineAudioContext};
 use web_audio_api::media_streams::{MediaStream, MediaStreamTrack};
@@ -38,7 +39,9 @@ pub impl AudioContext {
         let callback = Arc::new(callback);
         self.set_onstatechange(move |event| {
             let callback_cloned = callback.clone();
-            flutter_rust_bridge::spawn(async move { callback_cloned(event).await });
+            FLUTTER_RUST_BRIDGE_HANDLER
+                .async_runtime()
+                .spawn(async move { callback_cloned(event).await });
         })
     }
 }
@@ -50,7 +53,9 @@ pub impl OfflineAudioContext {
         callback: impl Fn(OfflineAudioCompletionEvent) -> DartFnFuture<()> + Send + Sync + 'static,
     ) {
         self.set_oncomplete(move |event| {
-            flutter_rust_bridge::spawn(async move { callback(event).await });
+            FLUTTER_RUST_BRIDGE_HANDLER
+                .async_runtime()
+                .spawn(async move { callback(event).await });
         })
     }
 }
@@ -70,7 +75,9 @@ macro_rules! handle_audio_node_trait_impls_override {
                 callback: impl Fn(String) -> DartFnFuture<()> + Send + 'static,
             ) {
                 self.set_onprocessorerror(Box::new(|event| {
-                    flutter_rust_bridge::spawn(async move { callback(event.message).await });
+                    FLUTTER_RUST_BRIDGE_HANDLER
+                        .async_runtime()
+                        .spawn(async move { callback(event.message).await });
                 }))
             }
         }
@@ -111,7 +118,7 @@ macro_rules! handle_audio_scheduled_source_node_trait_impls_override {
                     callback: impl Fn(Event) -> DartFnFuture<()> + Send + 'static,
                 ) {
                     self.set_onended(Box::new(|event| {
-                        flutter_rust_bridge::spawn(async move { callback(event).await });
+                        FLUTTER_RUST_BRIDGE_HANDLER.async_runtime().spawn(async move { callback(event).await });
                     }))
                 }
             }

frb_rust/src/handler/implementation/executor.rs

@@ -39,6 +39,10 @@ impl<EL: ErrorListener, TP: BaseThreadPool, AR: BaseAsyncRuntime> SimpleExecutor
     pub fn thread_pool(&self) -> &TP {
         &self.thread_pool
     }
+
+    pub fn async_runtime(&self) -> &AR {
+        &self.async_runtime
+    }
 }
 
 impl<EL: ErrorListener + Sync, TP: BaseThreadPool, AR: BaseAsyncRuntime> Executor

frb_rust/src/handler/implementation/handler.rs

@@ -32,6 +32,10 @@ impl<TP: BaseThreadPool> DefaultHandler<TP> {
     pub fn thread_pool(&self) -> &TP {
         self.executor.thread_pool()
     }
+
+    pub fn async_runtime(&self) -> &SimpleAsyncRuntime {
+        self.executor.async_runtime()
+    }
 }
 
 /// The simple handler uses a simple thread pool to execute tasks.

frb_rust/src/lib.rs

@@ -44,7 +44,7 @@ pub use crate::rust2dart::sender::Rust2DartSendError;
 #[cfg(all(feature = "rust-async", feature = "thread-pool"))]
 pub use crate::rust_async::spawn_blocking_with;
 #[cfg(feature = "rust-async")]
-pub use crate::rust_async::{spawn, spawn_local, JoinHandle};
+pub use crate::rust_async::{spawn, spawn_local, BaseAsyncRuntime, JoinHandle};
 #[cfg(feature = "rust-async")]
 pub use crate::rust_auto_opaque::RustAutoOpaqueNom;
 #[allow(deprecated)]