Zof

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- Use regular Python dictionary for events instead of wrapping them in Event object.
- Fix _ReplyFuture in controller.py to handle asyncio API change, and fix streaming multipart requests.
- Change underlying oftr connection to use protocol-based implementation (instead of streams).
- Add -xp prefix to experimental performance command line arguments: -xp-uvloop, -xp-ujson, -xp-streams.
- Add command line arguments to conntest demo.
- Add reconnect interval command line option and more features to simulator demo.
- Fix support for --help command line argument.
- Rename "poststop" phase to "postflight".
- ofctl processing code now supports validation of field names and values.

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- Add rest_api demo handlers for /stats/portdesc, /stats/port/{dpid} (needed for faucet).
- Minor performance improvements. Fix cooperative yielding behavior.
- Add experimental demos for benchmarking (cbenchreply, zbench, oftr_bench).
- Include milliseconds in log timestamp.
- Add CodecError exception for use by zof codec.
- Add alpine docker image.

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- Add request_all() api.
- Add support for the --pidfile command line argument.
- Add zof.codec module with Python codec for encode/decode OF messages.
- Refactor CompiledMessage into a base class.
- Add argument to control number of ports in simulator demo app.
- Fix KeyError bug in datapath class.

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- Fix exception in datapath service caused by manually closed datapath.
- All fields support slash notation.
- zof.run() supports arguments passed as a list.
- Fixed zof.encode() function to support dict and ObjectView argument types.
- Fixed zof.encode() function so exception messages are strings, not bytes.

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- Exceptions in async tasks will be associated with the app that created the task.
- Add get() method to PktView.
- Added zof.encode() function.
- Added --sim-endpoint command line argument to simulator demo app.
- Handle failure in datapath service _get_ports() function.

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- Fix UDP tp_src/tp_dst bug in convert_from_ofctl.