I used this example mostly when testing how CLOCK_REALTIME interacts with
suspending the system and alike. I figure it can be useful for this kind of
testing.

---
 Cargo.toml           |  4 ++++
 examples/wait_for.rs | 20 ++++++++++++++++++++
 2 files changed, 24 insertions(+)
 create mode 100644 examples/wait_for.rs

diff --git a/Cargo.toml b/Cargo.toml
index 6bdf2b5..5ffa1d2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -13,3 +13,7 @@ libc = "0.2.126"
 chrono = "0.4.19"
 thiserror = "1.0.31"
 errno = "0.2.8"
+
+[dev-dependencies]
+# Examples use extra features.
+tokio = { version = "1", features = ["signal", "rt", "macros", "rt-multi-thread", "time"] }
diff --git a/examples/wait_for.rs b/examples/wait_for.rs
new file mode 100644
index 0000000..52d45aa
--- /dev/null
+++ b/examples/wait_for.rs
@@ -0,0 +1,20 @@
+use chrono::Duration;
+use chrono::Utc;
+
+/// Takes a number as input and waits that many seconds before exiting.
+///
+/// Runnable with `cargo run --example=wait_for -- 2`.
+#[tokio::main]
+async fn main() {
+    let mut arguments = std::env::args();
+    arguments.next().expect("process executable has a name");
+    let arg1 = arguments.next().expect("first argument is specified");
+
+    let duration: i64 = arg1.parse().expect("first argument is a valid integer");
+    let duration = Duration::seconds(duration);
+
+    let timeout = Utc::now() + duration;
+    tokio_walltime::sleep_until(timeout)
+        .await
+        .expect("timer completes okay");
+}
-- 
2.39.1