@Override
  public boolean caresAboutSource(String name) {
    return caresAbout(Expression.PartialInput.ofSource(name));
  }
Call {@code handler} for different events based on which interfaces {@code handler} implements:
{@link OsmRelationPreprocessor}, {@link FinishHandler}, {@link TilePostProcessor} or {@link LayerPostProcessor}.
planetiler-core/src/main/java/com/onthegomap/planetiler/ForwardingProfile.java