Metal Synchronization problem

In the official ducument article 'Image Filter Graph with Heaps and Fences',

there is a initialise function initWithMetalKitView which call createScratchHeap to blits the contents of _imageTextures[i] to heapTexture.

Is there a prossibility that before the blit completed the commands in the drawInMTKView would read the uncompleted texture resource?