TileDiscardPolicy how to discard all tiles

Hello,

Grid imagery provider has read only undefined tilediscard policy. I want to create all tiles requested to be drawn all the time instead of using cached tiles. I couldn’t find a way to discard tiles everytime user zooms in or out. Cesium sometimes uses previously drawn tiles at different scales and I don’t want that to be happened cause in higher zoom levels I am drawing some things on canvas given by requestImage function.

Basically I need a TileDiscardPolicy that says “discard every tile when zoom happens” but I couldn’t find a way.

Thank you, regards