completion: Debug and query for barrier connection

libs/utils/src/completion.rs

@@ -8,6 +8,21 @@ pub struct Completion {
     _token: TaskTrackerToken,
 }
 
+impl std::fmt::Debug for Completion {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("Completion")
+            .field("siblings", &self._token.task_tracker().len())
+            .finish()
+    }
+}
+
+impl Completion {
+    /// Returns true if this completion is associated with the given barrier.
+    pub fn blocks(&self, barrier: &Barrier) -> bool {
+        TaskTracker::ptr_eq(self._token.task_tracker(), &barrier.0)
+    }
+}
+
 /// Barrier will wait until all clones of [`Completion`] have been dropped.
 #[derive(Clone)]
 pub struct Barrier(TaskTracker);