Vendor dependencies

Let's see how I like this workflow.

vendor/iana-time-zone/examples/get_timezone.rs

@@ -0,0 +1,6 @@
+use iana_time_zone::{get_timezone, GetTimezoneError};
+
+fn main() -> Result<(), GetTimezoneError> {
+    println!("{}", get_timezone()?);
+    Ok(())
+}

vendor/iana-time-zone/examples/stress-test.rs

@@ -0,0 +1,25 @@
+use std::sync::atomic::{AtomicUsize, Ordering};
+use std::thread::spawn;
+
+use iana_time_zone::get_timezone;
+
+const THREADS: usize = 10;
+const ITERATIONS: usize = 100_000;
+
+static COUNT: AtomicUsize = AtomicUsize::new(0);
+
+fn main() {
+    let mut threads = Vec::with_capacity(THREADS);
+    for _ in 0..THREADS {
+        threads.push(spawn(|| {
+            for _ in 0..ITERATIONS {
+                get_timezone().unwrap();
+                COUNT.fetch_add(1, Ordering::Relaxed);
+            }
+        }));
+    }
+    for thread in threads {
+        thread.join().unwrap();
+    }
+    assert_eq!(COUNT.load(Ordering::SeqCst), THREADS * ITERATIONS);
+}