Add support for custom message parsing.

[artificial-aidan]

Ran into an issue where we needed control of the message parsing functionality. Specifically the ability to include default field values. Set it up so that it works the same as default, but a custom parsing class can be passed in.

Just did the async side for now, can port to the sync side if wanted.

[ViridianForge]

One question about the implementation, but the spirit looks good.

Do you have a gut feel on whether there may be numerous different MessageProtocol implementation the library may want to support in the future?

I ask, because the client classes are feeling a bit hefty already, and it may be worthwhile to start considering breaking the code apart a bit in the near future.

[artificial-aidan]

One question about the implementation, but the spirit looks good.

Do you have a gut feel on whether there may be numerous different MessageProtocol implementation the library may want to support in the future?

I ask, because the client classes are feeling a bit hefty already, and it may be worthwhile to start considering breaking the code apart a bit in the near future.

So my attempt here was to make a straightforward to use custom message parser, CustomArgumentParsers. Which lets you set the keyword args for MessageToDict, while also allowing someone to expand if they wanted to do something completely different (json grpc or something) without having to change the library.

So 90% of people probably won't use custom parsers, 9% of people will use the built in custom parser with custom arguments, and 1% can write their own parser implementation.

[ViridianForge]

Thanks for answering my questions. All in all looks good - feel free to merge at your leisure, or, I'll go ahead and merge it in when I get some time later this week to work on a new release, as we slated those deprecated methods to be removed in 0.1.17.

[artificial-aidan]

Thanks for answering my questions. All in all looks good - feel free to merge at your leisure, or, I'll go ahead and merge it in when I get some time later this week to work on a new release, as we slated those deprecated methods to be removed in 0.1.17.

I don't believe I have write permissions on the repo. Happy to wait for 0.1.17

[ViridianForge]

Well, I'll get ya'll into develop at least, so I can build upon your commits. Thanks as always for the contributions1