Expose Ticker.startTime so users know the start time and the absolute time #115901
Description
Related: #113828 - This PR is closed and is requested to submit an issue here.
I will submit PRs once there is an approach that is allowed :)
Use case
The https://github.com/fzyzcjy/flutter_smooth is a package that "achieve ~60 FPS, no matter how heavy the tree is to build/layout". In order to implement it, this change seems to be needed.
More specifically, when implementing the ballistic shifting animation of (Smooth)ListView, I need to synchronize the clock of real ListView and the SmoothShift. If it is not synchronized, for example, ListView may think it should shift 50px by ballistic animation at frame 10, while SmoothShift wrongly thinks it is 60px, thus causing weird jump feeling when users look at it.
Related code is around https://github.com/fzyzcjy/flutter_smooth/blob/f8bc23932c9cd75e787e17029b249c48bfdee044/packages/smooth/lib/src/drop_in/list_view/shift.dart#L352.
Proposal
As is shown in the PR, I originally proposed to allow users to know the (absolute) start time.