Add `.runtime()`-emit to `._invoke()` to report final result msg in the child

tractor/_rpc.py

@@ -650,6 +650,10 @@ async def _invoke(
                 )
                 # set and shuttle final result to "parent"-side task.
                 ctx._result = res
+                log.runtime(
+                    f'Sending result msg and exiting {ctx.side!r}\n'
+                    f'{return_msg}\n'
+                )
                 await chan.send(return_msg)
 
             # NOTE: this happens IFF `ctx._scope.cancel()` is

tractor/_runtime.py

@@ -840,8 +840,10 @@ class Actor:
             )]
         except KeyError:
             report: str = (
-                'Ignoring invalid IPC ctx msg!\n\n'
-                f'<=? {uid}\n\n'
+                'Ignoring invalid IPC msg!?\n'
+                f'Ctx seems to not/no-longer exist??\n'
+                f'\n'
+                f'<=? {uid}\n'
                 f'  |_{pretty_struct.pformat(msg)}\n'
             )
             match msg: