add latency test

test_latency.py

@@ -0,0 +1,13 @@
+#!/usr/bin/python
+
+import sys
+import time
+
+
+before = time.time()
+
+for line in sys.stdin:
+    if 'HTTP/1.1 ' in line:
+        diff = time.time() - before
+        print 'headline %dms' % (diff * 1000)
+