+//!
+//! Most of the crate's logic is feature-gated, and *all dependencies are optional*:
+//! * By default, the `validate` feature is set, using `ring` to validate DNSSEC signatures and
+//! proofs using the [`validation`] module.
+//! * The `std` feature enables the [`query`] module, allowing for the building of proofs by
+//! querying a recursive resolver over TCP.
+//! * The `tokio` feature further enables async versions of the [`query`] methods, doing the same
+//! querying async using `tokio`'s TCP streams.
+//! * Finally, the crate can be built as a binary using the `build_server` feature, responding to
+//! queries over HTTP GET calls to `/dnssecproof?d=domain.name.&t=RecordType` with DNSSEC
+//! proofs.