diff --git a/http2/adapter/oghttp2_session.h b/http2/adapter/oghttp2_session.h
index 916ef08..0160b7d 100644
--- a/http2/adapter/oghttp2_session.h
+++ b/http2/adapter/oghttp2_session.h
@@ -40,7 +40,8 @@
   // sent.
   void StartGracefulShutdown();
 
-  // Invokes the visitor's OnReadyToSend() method for serialized frame data.
+  // Invokes the visitor's OnReadyToSend() method for serialized frames and
+  // DataFrameSource::Send() for data frames.
   int Send();
 
   int32_t SubmitRequest(absl::Span<const Header> headers,