benchmark and improve method parsing

amqp_transport/benches/parser.rs

@@ -0,0 +1,39 @@
+use amqp_transport::methods;
+use amqp_transport::methods::{Method, RandomMethod};
+use criterion::{black_box, criterion_group, criterion_main, Criterion};
+use rand::SeedableRng;
+
+fn random_method_from_seed(seed: u128) -> Method {
+    let mut rng = rand::rngs::StdRng::from_seed(
+        [seed.to_be_bytes(), seed.to_be_bytes()]
+            .concat()
+            .try_into()
+            .unwrap(),
+    );
+    Method::random(&mut rng)
+}
+
+fn serialize_method(method: Method) -> Vec<u8> {
+    let mut writer = Vec::new();
+    methods::write::write_method(method, &mut writer).unwrap();
+    writer
+}
+
+fn parse_method(c: &mut Criterion) {
+    let methods = (0..10000)
+        .map(random_method_from_seed)
+        .map(serialize_method)
+        .collect::<Vec<_>>();
+
+    c.bench_function("parse random methods", |b| {
+        b.iter(|| {
+            for data in &methods {
+                let result = methods::parse_method(black_box(data)).unwrap();
+                black_box(result);
+            }
+        })
+    });
+}
+
+criterion_group!(benches, parse_method);
+criterion_main!(benches);