unbound 0.4.0

This crate wraps libunbound from NLnet Labs. libunbound is an implementation of a DNS resolver, including cache and DNSSEC validation.

The interface provided follows libunbound closely:

• ub_ctx is wrapped by Context. OpenSSL is initialised when a Context is substantiated. Functions from libunbound that operate on ub_ctx are accessed using methods on Context.

• ub_result is wrapped by Answer. Methods on Answer are used to safely access the fields of ub_result.