def save(filename)
      stream.pos = 0
      all = stream.read.force_encoding('ascii-8bit')
      patches.each do |pos, val|
        all[pos, val.size] = val
      end
      IO.binwrite(filename, all)
    end
def save(filename)
      stream.pos = 0
      all = stream.read.force_encoding('ascii-8bit')
      patches.each do |pos, val|
        all[pos, val.size] = val
      end
      IO.binwrite(filename, all)
    end
Apply patches and save as +filename+.

 @param [String] filename
 @return [void]