public OptionalThing<Integer> getLastReturnCode() {
            return OptionalThing.of(200);
        }

        @Override
        public java.util.Map<String, org.dbflute.mail.send.supplement.attachment.SMailReadAttachedData> getSavedAttachmentMap() {
            return java.util.Collections.emptyMap();
        }

        @Override
        public java.util.List<jakarta.mail.Address> getSavedToList() {