diff --git a/src/shared/util.js b/src/shared/util.js
index 5777a43b7..9bd0ff1b1 100644
--- a/src/shared/util.js
+++ b/src/shared/util.js
@@ -1483,6 +1483,7 @@ MessageHandler.prototype = {
         if (this.isCancelled) {
           return;
         }
+        this.isCancelled = true;
         sendStreamRequest({ stream: 'close', });
         delete self.streamSinks[streamId];
       },