core: introduce `resource.read_return` (#14331)

1 files changed, 11 insertions, 1 deletions

diff --git a/core/resources.rs b/core/resources.rs
index 9a1447392..ae4ef7394 100644
--- a/core/resources.rs
+++ b/core/resources.rs
@@ -36,7 +36,17 @@ pub trait Resource: Any + 'static {
   }
 
   /// Resources may implement `read()` to be a readable stream
-  fn read(self: Rc<Self>, _buf: ZeroCopyBuf) -> AsyncResult<usize> {
+  fn read(self: Rc<Self>, buf: ZeroCopyBuf) -> AsyncResult<usize> {
+    Box::pin(async move {
+      let (nread, _) = self.read_return(buf).await?;
+      Ok(nread)
+    })
+  }
+
+  fn read_return(
+    self: Rc<Self>,
+    _buf: ZeroCopyBuf,
+  ) -> AsyncResult<(usize, ZeroCopyBuf)> {
     Box::pin(futures::future::err(not_supported()))
   }