Clear font texture at runtime

HI guys,

I want to have an image for every characters in a font and I want to generate those textures at runtime.
I did that by call the function font.RequestCharactersInTexture but the problem is when I call that function, the texture contains all characters which i requested before like this:

Could you tell me how can I clear requested characters in font texture, Thank you guys very much

If you are using Text Mesh Pro 1.4 with Dynamic SDF, then

public void ClearFontAssetData(bool setAtlasSizeToZero = false)