how to get centerbutton instanse from parent?

hi, in my app i would be use tap target view to create live help, so for this purpose must be get center button position to view tap target position,, for this How can i to get center button instance ?

No file, test, or entry point is named. Start by reviewing the library's public navigation-view API and how the center button is created or exposed. Confirm whether the requested result is access to the existing center button instance or its position, then document or test the supported behavior.

Written by the indexing model from the issue text.