One entry of a TileScheduler's trace (Observer).
public TileSchedulerEvent(TileEventKind Kind, Tile Tile, TilePriority Priority, bool IsPlaceholder, long Bytes)
What happened.
The tile.
Why the scheduler wanted it when this happened.
Whether it is a page's low-resolution placeholder.
The bytes accounted against the budget right after this happened.
Spec #33 viewer capabilities 1, 3 and 13.