fix: unify stream types with trait object

Co-authored-by: aider (openai/andrew/openrouter/deepseek/deepseek-chat-v3.1) <aider@aider.chat>

src/services/async_item_service.rs

@@ -240,22 +240,24 @@ impl AsyncItemService {
         let stream = tokio_stream::wrappers::ReceiverStream::new(rx);
         
         // If length is specified, we need to limit the stream
-        let limited_stream = if length > 0 {
+        // Use a trait object to ensure both branches have the same type
-            // We need to track how many bytes we've sent
+        let limited_stream: std::pin::Pin<Box<dyn tokio_stream::Stream<Item = Result<tokio_util::bytes::Bytes, std::io::Error>> + Send>> = 
-            let mut bytes_sent = 0;
+            if length > 0 {
-            let limited = stream.take_while(move |result| {
+                // We need to track how many bytes we've sent
-                if bytes_sent >= length {
+                let mut bytes_sent = 0;
-                    return false;
+                let limited = stream.take_while(move |result| {
-                }
+                    if bytes_sent >= length {
-                if let Ok(chunk) = result {
+                        return false;
-                    bytes_sent += chunk.len() as u64;
+                    }
-                }
+                    if let Ok(chunk) = result {
-                true
+                        bytes_sent += chunk.len() as u64;
-            });
+                    }
-            Box::pin(limited)
+                    true
-        } else {
+                });
-            Box::pin(stream)
+                Box::pin(limited)
-        };
+            } else {
+                Box::pin(stream)
+            };
         
         Ok((limited_stream, mime_type))
     }