How to use LongRunningTool in Long Execution situation other than "HITL"

[maxx1958]

It's not "HITL."
the tool has a long execution time, so when the user has to wait,

I wonder how to turn the user so that user can ask the next question without blocking(waiting).
and
when the tool is completed, it should be able to inform the user.

The example mentions only a case for HITL.
HITL injects new_message from outside back to Agent.
but. I want to know it without user input(like approval)

https://github.com/google/adk-python/tree/main/contributing/samples/tools/long_running_functions

I am curious about the process from start to in-progress to complete ( not HITL ).

how agent know tool is completed. and how to get result of tool?