Add comment about json encoder back

Author: maszyk99

splunklib/searchcommands/internals.py

@@ -669,6 +669,7 @@ def _write_record(self, record):
         # We may be running under PyPy 2.5 which does not include the _json module
         _iterencode_json = JSONEncoder(separators=(',', ':')).iterencode
     else:
+        # Creating _iterencode_json this way yields a two-fold performance improvement on Python 2.7.9 and 2.7.10
         from json.encoder import encode_basestring_ascii
 
         @staticmethod