getCurrentPageIndex abstract method
Returns the index of the current page. The index corresponds to its position
in the pages array passed to the initializeRoutes method of the initiator.
The index starts from 0.
This is added to provide more info about the current position of the page in the participator array.
This value is obtain by traversing the doubly-linked list data of all pages
in the left direction until we reach the first element. This value is not
cached as a static index value as we'd introduce the overhead of making sure
that the index is always accurate. For example, if you use Navigator.pop
instead of dynamicRoutesParticipator.popCurrent, the static number will
not be accurate.
Implementation
int getCurrentPageIndex(Widget currentPage);