diff --git a/lib/src/async_db.rs b/lib/src/async_db.rs
index e5b751d..4990eab 100644
--- a/lib/src/async_db.rs
+++ b/lib/src/async_db.rs
@@ -146,6 +146,8 @@ where
 use pin_project::pin_project;
 
 #[pin_project]
+/// FIXME: not really async
+/// only work when ..push.poll() returns Ready immediately
 pub struct WriterSink<'a, T>
 where
     T: bincode::Encode,
@@ -173,7 +175,7 @@ where
 
         let item = this.item.take().unwrap();
 
-        let push_fut = this.writer.push(item);
+        let push_fut = this.writer.push(item); // FIXME:: how to save this future???
         pin_mut!(push_fut);
         push_fut.poll(ctx)
     }
@@ -333,6 +335,7 @@ where
             return Poll::Ready(None);
         }
 
+        // FIXME: mayby work only if reader.get().poll() return Ready immediately
         let future = self.reader.get(self.index.unwrap());
         pin_mut!(future);
         match Pin::new(&mut future).poll(cx) {