Function read_era_dir 

pub fn read_era_dir(
    dir: impl AsRef<Path> + Send + Sync + 'static,
) -> Result<impl Stream<Item = Result<EraLocalMeta>> + Send + Sync + 'static + Unpin>

Creates a new ordered asynchronous [Stream] of consensus .era files read from dir.

Unlike read_dir, consensus .era files ship no checksums.txt, and their filenames encode an era (slot) number rather than a block number. Files are streamed in ascending era order; the import pipeline filters out blocks already present, so no block-level start_from skipping is done here.