get Annotated Layer Feature
Get content with type AnnotatedLayerFeature from the variant.
Return
content with type AnnotatedLayerFeature
Throws
if the content of the variant does not have type AnnotatedLayerFeature
Get content with type AnnotatedLayerFeature from the variant.
content with type AnnotatedLayerFeature
if the content of the variant does not have type AnnotatedLayerFeature