docs: private static void copyToLocal(Metadata src, Path dst) throws IOException {
      FileChannel dstCh = FileChannel.open(
          dst, StandardOpenOption.WRITE, StandardOpenOption.CREATE_NEW);
      ReadableByteChannel srcCh = FileSystems.open(src.resourceId());
      long srcSize = src.sizeBytes();
      long copied = 0;
      do {
        copied += dstCh.transferFrom(srcCh, copied, srcSize - copied);
      } while (copied < srcSize);
      dstCh.close();
      srcCh.close();
      Preconditions.checkState(copied == srcSize);
    }