add benchmark

benches/benchmark.rs

@@ -0,0 +1,19 @@
+use criterion::{black_box, criterion_group, criterion_main, Criterion};
+
+use departure::response::Response;
+
+use std::fs::read_to_string;
+
+fn load_json() -> String {
+    read_to_string("benches/reply.json").unwrap()
+}
+
+fn criterion_benchmark(c: &mut Criterion) {
+    let content = load_json();
+    c.bench_function("parse JSON", |b| {
+        b.iter(|| serde_json::from_str::<'_, Response>(black_box(&content)))
+    });
+}
+
+criterion_group!(benches, criterion_benchmark);
+criterion_main!(benches);