Defer task name formatting also in Python Task impl

Author: itamaro

Lib/asyncio/tasks.py

@@ -103,8 +103,10 @@ def __init__(self, coro, *, loop=None, name=None, context=None):
             self._log_destroy_pending = False
             raise TypeError(f"a coroutine was expected, got {coro!r}")
 
+        self._task_name_counter = 0
         if name is None:
-            self._name = f'Task-{_task_name_counter()}'
+            self._task_name_counter = _task_name_counter()
+            self._name = None
         else:
             self._name = str(name)
 
@@ -143,6 +145,8 @@ def get_context(self):
         return self._context
 
     def get_name(self):
+        if self._name is None:
+            self._name = f'Task-{self._task_name_counter}'
         return self._name
 
     def set_name(self, value):