RisingWave Community - Is it possible to decode protobuf as a transformation step or only from a source directly?

Currently, the recommended way to parse protobuf messages is directly from a source.
Storing raw binary in addition to parsing with different versions of protobuf files can be achieved by creating a new source every time with different protobuf definitions.
Using a UDF for parsing protobuf messages is an alternative approach.
A proposed protobuf_decode(bytea, proto_url) function may not significantly differ from using a UDF, as it still requires a network hop to access the remote proto_url.