Add zid stringify bench test

Signed-off-by: Dhammika Pathirana <dhammika@gmail.com>

zenith_utils/Cargo.toml

@@ -37,3 +37,8 @@ bytes = "1.0.1"
 hex-literal = "0.3"
 tempfile = "3.2"
 webpki = "0.21"
+criterion = "0.3"
+
+[[bench]]
+name = "benchmarks"
+harness = false

zenith_utils/benches/benchmarks.rs

@@ -0,0 +1,22 @@
+#![allow(unused)]
+
+use criterion::{criterion_group, criterion_main, Criterion};
+use zenith_utils::zid;
+
+pub fn bench_zid_stringify(c: &mut Criterion) {
+    // Can only use public methods.
+    let ztl = zid::ZTenantTimelineId::generate();
+
+    c.bench_function("zid.to_string", |b| {
+        b.iter(|| {
+            // FIXME measurement overhead?
+            //for _ in 0..1000 {
+            //    ztl.tenant_id.to_string();
+            //}
+            ztl.tenant_id.to_string();
+        })
+    });
+}
+
+criterion_group!(benches, bench_zid_stringify);
+criterion_main!(benches);