# File lib/rack/deflater.rb, line 56
  def self.gzip(body, mtime)
    io = StringIO.new
    gzip = Zlib::GzipWriter.new(io)
    gzip.mtime = mtime

    # TODO: Add streaming
    body.each { |part| gzip << part }

    gzip.close
    return io.string
  end