compute_checksum_in_chunks

# File activestorage/app/models/active_storage/blob.rb, line 332
    def compute_checksum_in_chunks(io)
      raise ArgumentError, "io must be rewindable" unless io.respond_to?(:rewind)

      OpenSSL::Digest::MD5.new.tap do |checksum|
        read_buffer = "".b
        while io.read(5.megabytes, read_buffer)
          checksum << read_buffer
        end

        io.rewind
      end.base64digest
    end