class Aws::Plugins::ChecksumAlgorithm

def self.calculate_checksum(algorithm, body)
  digest = ChecksumAlgorithm.digest_for_algorithm(algorithm)
  if body.respond_to?(:read)
    ChecksumAlgorithm.update_in_chunks(digest, body)
  else
    digest.update(body)
  end
  digest.base64digest
end