public void toConfig(StringBuilder cfg, String prefix) {
        int numTables = tables.size();
        if (numTables > 0) {
            cfg.append(prefix).append("routingtable[").append(numTables).append("]\n");
            for (int i = 0; i < numTables; ++i) {
                tables.get(i).toConfig(cfg, prefix + "routingtable[" + i + "].");
            }
        }
    }
Appends the content of this to the given config string builder.

@param cfg    The config to add to.
@param prefix The prefix to use for each add.
messagebus/src/main/java/com/yahoo/messagebus/routing/RoutingSpec.java