Migrate Python C extension to Cython (#3541)

python/ray/profiling.py

@@ -97,6 +97,10 @@ class Profiler(object):
                 time.sleep(1)
                 self.flush_profile_data()
         except AttributeError:
+            # TODO(suquark): It is a bad idea to ignore "AttributeError".
+            # It has caused some very unexpected behaviors when implementing
+            # new features (related to AttributeError).
+
             # This is to suppress errors that occur at shutdown.
             pass
 
@@ -120,7 +124,7 @@ class Profiler(object):
             component_type = "driver"
 
         self.worker.raylet_client.push_profile_events(
-            component_type, ray.ObjectID(self.worker.worker_id),
+            component_type, ray.UniqueID(self.worker.worker_id),
             self.worker.node_ip_address, events)
 
     def add_event(self, event):