Add crash example

examples/crash.rs

@@ -0,0 +1,34 @@
+extern crate jwalk;
+
+use jwalk::{WalkDir, Parallelism};
+use rayon::prelude::*;
+
+fn main() {
+    let rounds = vec![0, 1];
+
+    rayon::ThreadPoolBuilder::new()
+        .num_threads(1)
+        .build_global()
+        .expect("Failed to initialize worker thread pool");
+
+    let jwalk_pool = std::sync::Arc::new(
+        rayon::ThreadPoolBuilder::new()
+            .num_threads(1)
+            .build()
+            .unwrap(),
+    );
+
+    // Does finish if jwalk uses own pool with 1 thread
+    rounds.par_iter().for_each(|round| {
+        eprintln!("Round {round}…");
+        for _entry in WalkDir::new(".").parallelism(Parallelism::RayonExistingPool(jwalk_pool.clone())) {}
+        eprintln!("Round {round} completed");
+    });
+
+    // Does not finish if jwalk uses shared pool with 1 thread
+    rounds.par_iter().for_each(|round| {
+        eprintln!("Round {round}…");
+        for _entry in WalkDir::new(".") {}
+        eprintln!("Round {round} completed");
+    });
+}