@java.lang.Override
    public void writeTo(com.google.protobuf.CodedOutputStream output) throws java.io.IOException {
        for (UserRelationship userRelationship : userRelationships_) {
            output.writeMessage(1, userRelationship);
        }
        if (((bitField0_ & 0x00000001) != 0)) {
            output.writeInt64(2, lastUpdatedDate_);
        }
        getUnknownFields().writeTo(output);
    }
<code>optional int64 last_updated_date = 2;</code>

@return The lastUpdatedDate.
turms-server-common/src/main/java/im/turms/server/common/access/client/dto/model/user/UserRelationshipsWithVersion.java