v3.2.0
Add Protobuf.ignore_unknown_fields config option (default true).
When setting this option to false, attempts to assign a value to an unknown field on a message will raise a FieldNotDefinedError. Assignment is protected in the initializer (hash argument), Message.encode class method, and the instance-level bracket method Message#[]=.
Decoding messages should ignore this behavior as it is a core tenet of the protocol buffers specification.