исправить: закрыть ревью сквозной корреляции

crates/crank-trace/src/lib.rs

@@ -63,24 +63,13 @@ impl Stage {
             ),
         }
     }
-
-    pub fn db_span(self, operation: DbOperation) -> Option<Span> {
-        if self != Self::DbQuery {
-            return None;
-        }
-        let span = self.span();
-        span.record("db.operation", operation.as_str());
-        Some(span)
-    }
 }
 
 pub async fn observe_db_query<T, E>(
     operation: DbOperation,
     future: impl Future<Output = Result<T, E>>,
 ) -> Result<T, E> {
-    let span = Stage::DbQuery
-        .db_span(operation)
-        .expect("database operation requires db.query stage");
+    let span = operation.span();
     let result = future.instrument(span.clone()).await;
     match &result {
         Ok(_) => StageOutcome::Success.record(&span),
@@ -182,6 +171,12 @@ pub enum DbOperation {
 }
 
 impl DbOperation {
+    pub fn span(self) -> Span {
+        let span = Stage::DbQuery.span();
+        span.record("db.operation", self.as_str());
+        span
+    }
+
     pub const fn as_str(self) -> &'static str {
         match self {
             Self::MachineAccessRead => "machine_access.read",