Java byte[] properties are translated into bytes Proto fields.
The JSON representation of those instances is the Base64 encoding of the binary.

{"_type":"Item","code":"c7","byteVector":"BwcH","floatVector":[1.1,1.1,1.1],"buggy":"bla bla bla"}

We want to provide al alternative way to specify the bytes value using JSON, that is using a JSON array:

{"_type":"Item","code":"c7","byteVector":[7,7,7],"floatVector":[1.1,1.1,1.1],"buggy":"bla bla bla"}