Function animated_text_key 

pub fn animated_text_key(
    content: &TextContent,
    style: &TextStyle,
    size: PictureSize,
    time: MediaTime,
) -> u64

text_key for content in style shown time after its holder started. Without animators this is the static key; otherwise the runs and time are mixed in, so each moment of an animation is a distinct text. Never zero.