Add key lifecycle management (PR #459)

Cargo.toml

@@ -74,7 +74,7 @@ zonefile    = ["bytes", "serde", "std"]
 # Unstable features
 unstable-client-transport = ["moka", "net", "tracing"]
 unstable-server-transport = ["arc-swap", "chrono/clock", "libc", "net", "siphasher", "tracing"]
-unstable-sign = ["std", "dep:secrecy", "unstable-validate"]
+unstable-sign = ["std", "dep:secrecy", "unstable-validate", "time/formatting"]
 unstable-stelline = ["tokio/test-util", "tracing", "tracing-subscriber", "tsig", "unstable-client-transport", "unstable-server-transport", "zonefile"]
 unstable-validate = ["bytes", "std", "ring"]
 unstable-validator = ["unstable-validate", "zonefile", "unstable-client-transport"]
@@ -85,6 +85,7 @@ unstable-zonetree = ["futures-util", "parking_lot", "rustversion", "serde", "std
 arbitrary = ["dep:arbitrary"]
 
 [dev-dependencies]
+itertools = "0.13.0"
 lazy_static        = { version = "1.4.0" }
 rstest             = "0.19.0"
 rustls-pemfile     = { version = "2.1.2" }
@@ -152,6 +153,10 @@ required-features = ["zonefile", "net", "unstable-client-transport", "unstable-z
 name = "query-routing"
 required-features = ["net", "unstable-client-transport", "unstable-server-transport", "tracing-subscriber"]
 
+[[example]]
+name = "keyset"
+required-features = ["serde", "unstable-sign"]
+
 # This example is commented out because it is difficult, if not impossible,
 # when including the sqlx dependency, to make the dependency tree compatible
 # with both `cargo +nightly update -Z minimal versions` and the crate minimum