This class contains window animation frame statistics. For example, a window animation is usually performed when the application is transitioning from one activity to another. The frame statistics are a snapshot for the time interval from FrameStats.StartTimeNano to FrameStats.EndTimeNano.

The key idea is that in order to provide a smooth user experience the system should run window animations at a specific time interval obtained by calling FrameStats.RefreshPeriodNano. If the system does not render a frame every refresh period the user will see irregular window transitions. The time when the frame was actually presented on the display by calling FrameStats.GetFramePresentedTimeNano(int).

[Android Documentation]