One thing that’s been bugging me lately is that the design of the plugin API leads to some bloat in the plugins - all of the Message-related classes have to be included in both the plugins and the host application. In order to fix this, all Message objects have to be maintained by the host app, and the plugins will deal with them using references. This also deals with the inefficiency of passing messages back and forth by serializing them.
The down side is that this approach loses the transparency aspect of the API, which I rather liked - the exact same code could be compiled as a plugin, or build into the host app. I think it’s a good sacrifice though, and if the transparency thing tuns out to be really desirable I can get it back by converting everything else to use message references too. But that would be a major change, and I doubt it would really be necessary.
Meanwhile, most of my time is going into writing about Volley instead of writing Volley.