I did notice that protobuf schema translator supports nullable for proto fiels [1]. E.g. if I want to a nullable string, then in proto I can use `google.protobuf.StringValue` and schema will look fine.
However, fromRow creator does not support this and throw exception if it is presented with row instance with null value. It tries to pass this null to a `StringValue` while proto way would be probably ignoring the set in that case. I can submit a failing test case and JIRA but want to check first if this is supposed to be supported - having row with nulls handled and creating instance of compatible protobuf. Thanks, Jozo [1] https://github.com/apache/beam/blob/master/sdks/java/extensions/protobuf/src/main/java/org/apache/beam/sdk/extensions/protobuf/ProtoSchemaTranslator.java#L106
