--- a/mercurial/wireprotov2peer.py	Tue Sep 04 12:36:33 2018 -0400
+++ b/mercurial/wireprotov2peer.py	Wed Aug 22 10:29:30 2018 -0700
@@ -136,6 +136,9 @@
         response = self._responses[frame.requestid]
 
         if action == 'responsedata':
+            # This buffers all data until end of stream is received. This
+            # is bad for performance.
+            # TODO make response data streamable
             response.b.write(meta['data'])
 
             if meta['eos']: