private PortsMeta register(int offset, String meta) {
        // Allocate new LinkedLists on each element up-to-and-including offset
        for (int i = ports.size(); i <= offset; i++) {
            ports.add(i, new LinkedList<>());
        }
        ports.get(offset).addFirst(meta);

        return this;
    }
Register a given metainfo string to the port at offset.

@param offset 0-based index to identify the port
@param meta a String to be added to the given ports meta set
@return this for convenient chaining
config-model/src/main/java/com/yahoo/vespa/model/PortsMeta.java