add
expect fun addUnknownField(tag: Int, fieldEncoding: FieldEncoding, value: Any?): Message.Builder<M, B>
actual fun addUnknownField(tag: Int, fieldEncoding: FieldEncoding, value: Any?): Message.Builder<M, B>
actual fun addUnknownField(tag: Int, fieldEncoding: FieldEncoding, value: Any?): Message.Builder<M, B>
actual fun addUnknownField(tag: Int, fieldEncoding: FieldEncoding, value: Any?): Message.Builder<M, B>