Split iced_futures into different backend implementations

futures/src/backend/wasm/wasm_bindgen.rs

@@ -0,0 +1,15 @@
+//! A `wasm-bindgein-futures` backend.
+
+/// A `wasm-bindgen-futures` executor.
+#[derive(Debug)]
+pub struct Executor;
+
+impl crate::Executor for Executor {
+    fn new() -> Result<Self, futures::io::Error> {
+        Ok(Self)
+    }
+
+    fn spawn(&self, future: impl futures::Future<Output = ()> + 'static) {
+        wasm_bindgen_futures::spawn_local(future);
+    }
+}