bench: criterion suite for the extension hot paths

.gitignore

@@ -30,3 +30,6 @@ integration-tests/cdk.context.json
 /CLAUDE_PERSONAL.md
 # Generated benchmark fixture corpus (see bottlecap/tests/fixtures/README.md)
 bottlecap/tests/fixtures/generated
+# Criterion baseline exports are machine specific; keep them as CI artifacts, not in git.
+bottlecap/benches/baselines/*.json
+bottlecap/target-linux-arm64

bottlecap/Cargo.toml

@@ -124,16 +124,49 @@ rmp-serde = { version = "1.3.1", default-features = false }
 flate2 = { version = "1.1", default-features = false, features = ["rust_backend"] }
 # fault-intake test harness: decode the `datadog-protos` metrics payloads
 protobuf = { version = "3.7", default-features = false }
+# Hot-path benchmark suite under `benches/`. See `benches/README.md`.
+criterion = { version = "0.5", default-features = false, features = ["cargo_bench_support", "async_tokio"] }
 
 [build-dependencies]
 # No external dependencies needed for the build script
 
+[lib]
+# `cargo bench` runs only the criterion targets under `benches/`, not the
+# libtest harness of the library and the binaries.
+bench = false
+
 [[bin]]
 name = "bottlecap"
+bench = false
 
 [[bin]]
 name = "bottlecap-test-mode"
 required-features = ["test-mode"]
+bench = false
+
+[[bench]]
+name = "logs"
+harness = false
+
+[[bench]]
+name = "traces"
+harness = false
+
+[[bench]]
+name = "invocation"
+harness = false
+
+[[bench]]
+name = "enhanced_metrics"
+harness = false
+
+[[bench]]
+name = "config"
+harness = false
+
+[[bench]]
+name = "init"
+harness = false
 
 [profile.dev]
 debug = true   # same as debuginfo=2 and no stripping