Function transform_anchor_preference 

pub fn transform_anchor_preference(
    view: &ViewHandle,
    transform: impl Fn(i64) -> i64 + 'static,
) -> ViewHandle

Apply .transformAnchorPreference(key:value:transform:).

The same shape, except the transform takes the running value inout — so x0 is a pointer to write back through rather than a result to produce.