sensible output for who waits on whom

test/test_scenario.py

@@ -34,16 +34,42 @@ async def b_branch(f):
     await f
 
 
+def name(t):
+    try:
+        # Python3.8
+        return t.get_name()
+    except AttributeError:
+        return f"Task-{id(t)}"
+
+
 async def test():
     import sys
 
-    # import awaitwhat
     await asyncio.sleep(0.1)
     print("### Python native")
-    for t in asyncio.Task.all_tasks():
+    for t in asyncio.all_tasks():
+        print(name(t))
         asyncio.base_tasks._task_print_stack(t, None, sys.stdout)
         print()
 
+    for t in asyncio.all_tasks():
+        waiter = t._fut_waiter
+        """
+        # FIXME waiter is not a Task, it's a:
+        * _asyncio.Future
+        * asyncio.tasks._GatheringFuture
+        * ...
+        * None
+        """
+        try:
+            waiter = ", ".join(map(name, waiter._children))
+        except AttributeError:
+            pass
+        print(f"{name(t)} -> {waiter}")
+
+    # Extended stack
+    # import awaitwhat
+
     for f in FUTURES:
         f.set_result(None)