Calculate md5 file checksum

digestfile.scala

Using.Manager { use =>
  val md  = MessageDigest.getInstance("MD5")
  val fis = use(Files.newInputStream(filePath))
  val dos = use(new DigestOutputStream(OutputStream.nullOutputStream(), md))
  fis.transferTo(dos)
  BigInt(1, md.digest()).formatted(s"%0${md.getDigestLength * 2}x")
}