code: public static File getFileSystemPath(File base, UUID shardUuid)
      {
          String uuid = shardUuid.toString().toLowerCase(ENGLISH);
          return base.toPath()
                  .resolve(uuid.substring(0, 2))
                  .resolve(uuid.substring(2, 4))
                  .resolve(uuid + FILE_EXTENSION)
                  .toFile();
      }
docs: Generate a file system path for a shard UUID.
  This creates a three level deep directory structure where the first
  two levels each contain two hex digits (lowercase) of the UUID
  and the final level contains the full UUID. Example:
  <pre>
  UUID: 701e1a79-74f7-4f56-b438-b41e8e7d019d
  Path: /base/70/1e/701e1a79-74f7-4f56-b438-b41e8e7d019d.orc
  </pre>
  This ensures that files are spread out evenly through the tree
  while a path can still be easily navigated by a human being.