Relative priority for this texture when reducing memory size in order to hit the memory budget.
When mipmap streaming is enabled, Unity will automatically reduce the size of textures until they fit into the texture streaming memory budget. This number is roughly a mipmap offset for the memory budget code. For example, with a priority of 2 Unity will try to use a mipmap two larger than other textures with a priority of 0. Negative values are also valid.