public void setExplicitRoutingSpec(RoutingSpec routing) {
        explicitRouting = routing;
    }
Sets the routing specification to include in the derived routing config. This needs to be invoked before
{@link #deriveCommonSettings(com.yahoo.config.model.ConfigModelRepo)} to be included.

@param routing the routing specification to include
config-model/src/main/java/com/yahoo/vespa/model/routing/Routing.java