= New Features

* A hash_public_cache plugin has been added, which allows preloading
  the digest cache for the hash_public plugin using a file, avoiding
  the need for the hash_public plugin to read files on first
  request for them to compute the digests.

    plugin :hash_public_cache, "path/to/cache_file.json"

    # Scan public directory, populate cache, and dump cache file.
    scan_hash_public_cache_dir
    dump_hash_public_cache_file

    # Populate cache from file at process startup
    load_hash_public_cache_file

= Other Improvements

* The hash_public plugin now uses OpenSSL::Digest instead of Digest
  if available for better performance.
