Regarding design tradeoffs: I am very skeptical that this can be made to work for the long run in a cross-language way without formalizing the on-the-wire contract via IDL or similar.
In my experience, while starting from a language to arrive at the serialization often feels more ergonomic (e.g. RPC style) in the start, it hides too much of what's going on from the users and over time suffers greatly from programming language / runtime changes - the latter multiplied by the number of languages or frameworks supported.
In my experience, while starting from a language to arrive at the serialization often feels more ergonomic (e.g. RPC style) in the start, it hides too much of what's going on from the users and over time suffers greatly from programming language / runtime changes - the latter multiplied by the number of languages or frameworks supported.