TODO

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    http://github.com/celery/celery/issues


- Widelane

    - Task logs errors + sends_events in the child processes

    - Move non-complex object message fields from the body
      to properties/application headers (task-message-format-v2)

        - this means that the worker will not have to deserialize
          payload to inspect these fields, and as such we may
          avoid the double depickling happening in the Main- and child
          processes.

    - Change worker internals to support applying a list
      of tasks instead of going task-by-task.

    - Buffering and calling map on tasks of the same type
      received in a short timeframe.

    - Also buffer acks(?)

    - This may also enable automatic batching alá celery.contrib.batches(?)

    - job.TaskRequest may be changed to a namedtuple instead, minimizing
      memory overhead, and will probably be faster too.

        - though this begs the question how and where the Request's methods will
          be implemented(?), some are easy to move to functions but others
          are not so fortunate.