@Override
    public OptionalLong limit() {
      try {
        return OptionalLong.of(fileStore.getUnallocatedSpace());
      } catch (IOException e) {
        return OptionalLong.empty();
      }
    }
Finds the {@link FileStore} that {@code path} will exist on.
planetiler-core/src/main/java/com/onthegomap/planetiler/util/ResourceUsage.java