Interface to 256-way radix trie for DNS lookups.
Missing data from a SOA/cut node.
Node of the trie
Make a new, empty trie.
Simple lookup function: just walk the trie.
Look up a DNS entry in the trie, with full return.
Return the data mapped from this key, making new data if there is none
Sort out flags for a key's node: call after adding or removing NS, SOA and
Iterate over all of the nodes in the trie.