Function any_contextual_var 

pub fn any_contextual_var(
    context_init: impl FnMut() -> AnyVar + Send + 'static,
    value_type: TypeId,
) -> AnyVar

Create a type erased contextualized variable.

The context_init closure must produce variables of the same value_type. The value type is needed to avoid contextualizing the variable for calls of AnyVar::downcast and AnyVar::value_type that often happen outside of the variable final context, such as in widget property capture.

See contextual_var for more details about contextualized variables.