add construction bench

lib/http-signatures/Cargo.toml

@@ -5,6 +5,10 @@ edition.workspace = true
 version.workspace = true
 license = "MIT OR Apache-2.0"
 
+[[bench]]
+name = "build_cavage_signature_string"
+harness = false
+
 [[bench]]
 name = "parse_cavage_header"
 harness = false

lib/http-signatures/benches/build_cavage_signature_string.rs

@@ -0,0 +1,38 @@
+use criterion::{criterion_group, criterion_main, Criterion};
+use http::{Method, Request, Uri};
+use std::hint::black_box;
+
+const CAVAGE_HEADER: &str =
+    r#"keyId="Test",algorithm="rsa-sha256",headers="(request-target) host date",signature="qdx""#;
+
+fn build_cavage_signature_string1(c: &mut Criterion) {
+    let signature_header = http_signatures::cavage::parse(CAVAGE_HEADER).unwrap();
+    let request = Request::builder()
+        .method(Method::GET)
+        .uri(Uri::from_static("/foo?param=value&pet=dog"))
+        .header("Host", "example.com")
+        .header("Date", "Sun, 05 Jan 2014 21:31:40 GMT")
+        .header("Content-Type", "application/json")
+        .header(
+            "Digest",
+            "SHA-256=X48E9qOokqqrvdts8nOJRJN3OWDUoyWxBf7kbu9DBPE=",
+        )
+        .header("Content-Length", "18")
+        .body(())
+        .unwrap();
+
+    c.bench_function("build_cavage_signature_string", |b| {
+        b.iter(|| {
+            let _ = black_box(http_signatures::cavage::signature_string::construct(
+                black_box(&request),
+                black_box(&signature_header),
+            ));
+        });
+    });
+}
+
+criterion_group!(
+    build_cavage_signature_string,
+    build_cavage_signature_string1
+);
+criterion_main!(build_cavage_signature_string);