diff -r 5bfffdbdc907 -r 76cba1ecf55f mercurial/bundle2.py
--- a/mercurial/bundle2.py	Tue May 26 23:36:31 2015 -0700
+++ b/mercurial/bundle2.py	Tue May 26 23:58:38 2015 -0700
@@ -1060,9 +1060,12 @@
             data = self._payloadstream.read()
         else:
             data = self._payloadstream.read(size)
+        self._pos += len(data)
         if size is None or len(data) < size:
+            if not self.consumed and self._pos:
+                self.ui.debug('bundle2-input-part: total payload size %i\n'
+                              % self._pos)
             self.consumed = True
-        self._pos += len(data)
         return data
 
     def tell(self):