@Override
    public void onUser(ObjectNode node) throws IOException {
        if (chain.hasMigrators()) {
            logger.info(Messages.i18n.format("DataMigrator.MigratingUser", node.get("username"))); //$NON-NLS-1$ //$NON-NLS-2$
            chain.migrateUser(node);
        }
        writer.writeUser(node);
    }
@see io.apiman.manager.api.migrator.IReaderHandler#onUser(com.fasterxml.jackson.databind.node.ObjectNode)
manager/api/migrator/src/main/java/io/apiman/manager/api/migrator/DataMigrator.java