private void addServerAndClientsForChains(ContainerDocproc docproc) {
        if (docproc != null)
            docproc.getChains().addServersAndClientsForChains();
    }
Processing that requires access across different plugins

@param root root config producer
@param configModelRepo a {@link ConfigModelRepo}
config-model/src/main/java/com/yahoo/vespa/model/builder/xml/dom/VespaDomBuilder.java