From https://developers.google.com/protocol-buffers/docs/encoding?csw=1, it seems that optional fields that are not set on the Writer side's schema won't be sent over the wire. That means the Reader does not receive the field.
If the Reader's schema includes the optional field without a default value, will it get set to its null equivalent automatically?
If the Reader's schema also contains a default value will it get set to its default value automatically?
And logically I guess if the Reader's schema does not include the field (but the Writer's does), then it will just disregard it.
