Temporarily drop cython from the dep list and try develop for travis.

.travis.yml

@@ -14,6 +14,6 @@ install:
     - travis_retry pip install --install-option='--no-cython-compile' cython
 script:
     # Try to use the site packages of cython we just installed
-    - tox --sitepackages
+    - tox --sitepackages --develop
 notifications:
   email: false

gevent/_socket2.py

@@ -296,10 +296,12 @@ class socket(object):
             timeleft = self.timeout
             end = time.time() + timeleft
             data_sent = 0
+            trips = 0
             while True:
+                trips += 1
                 data_sent += self.send(_get_memory(data, data_sent), flags, timeout=timeleft)
                 if data_sent >= len(data):
-                    return data_sent, 'timeout', self.timeout
+                    return data_sent, 'timeout', self.timeout, trips
                 timeleft = end - time.time()
                 if timeleft <= 0:
                     raise timeout('timed out')

tox.ini

@@ -5,7 +5,7 @@ envlist =
 [testenv]
 deps =
     greenlet
-    cython
+#    cython
 whitelist_externals =
     *
 commands =