chore: checkpoint before Python removal

vendor/tracing/benches/span_no_fields.rs

@@ -0,0 +1,13 @@
+use criterion::{criterion_group, criterion_main, Criterion};
+use tracing::{span, Level};
+
+mod shared;
+
+fn bench(c: &mut Criterion) {
+    shared::for_all_recording(&mut c.benchmark_group("span_no_fields"), |b| {
+        b.iter(|| span!(Level::TRACE, "span"))
+    });
+}
+
+criterion_group!(benches, bench);
+criterion_main!(benches);