log the reason when we restart the request

fix #110

restkit/wrappers.py

@@ -5,6 +5,7 @@
 
 import cgi
 import copy
+import logging
 import mimetypes
 import os
 from StringIO import StringIO
@@ -19,6 +20,8 @@
 from restkit.util import to_bytestring
 from restkit.util import parse_cookie
 
+log = logging.getLogger(__name__)
+
 class Request(object):
 
     def __init__(self, url, method='GET', body=None, headers=None):
@@ -143,6 +146,8 @@ def maybe_rewind(self, msg=""):
                     not isinstance(self.body, types.StringTypes):
                 raise RequestError("error: '%s', body can't be rewind."
                         % msg)
+        if log.isEnabledFor(logging.DEBUG):
+            log.debug("restart request: %s" % msg)
 
 
 class BodyWrapper(object):