add explicit timer method implementation

rest_framework/throttling.py

@@ -60,7 +60,6 @@ class SimpleRateThrottle(BaseThrottle):
     Previous request information used for throttling is stored in the cache.
     """
     cache = default_cache
-    timer = staticmethod(time.time)
     cache_format = 'throttle_%(scope)s_%(ident)s'
     scope = None
     THROTTLE_RATES = api_settings.DEFAULT_THROTTLE_RATES
@@ -131,6 +130,10 @@ class SimpleRateThrottle(BaseThrottle):
             return self.throttle_failure()
         return self.throttle_success()
 
+    def timer(self):
+        """Time in seconds since the epoch."""
+        return time.time()
+
     def throttle_success(self):
         """
         Inserts the current request's timestamp along with the key