FileEngine: expose native file types on different platforms (#1258)

* Get native file

* Correct visibility

packages/html/src/native_bind/native_file_engine.rs

@@ -1,3 +1,4 @@
+use std::any::Any;
 use std::path::PathBuf;
 
 use crate::FileEngine;
@@ -40,4 +41,9 @@ impl FileEngine for NativeFileEngine {
 
         Some(contents)
     }
+
+    async fn get_native_file(&self, file: &str) -> Option<Box<dyn Any>> {
+        let file = File::open(file).await.ok()?;
+        Some(Box::new(file))
+    }
 }