Macro protobuf_codec::protobuf_message_oneof_field_encoder

macro_rules! protobuf_message_oneof_field_encoder {
    ($num:expr, $field:expr) => { ... };
    ($num:expr, $field:expr,message) => { ... };
    ($num:expr, $field:expr,unsized_message) => { ... };
}

Auxiliary macro used for expanding $oneof_field argument of protobuf_message_field_encoder!.