def header
      header = client.header
      param[:header].each do |h|
        k, v = h.split(": ")
        header[k] = v
      end
      header
    end
def header
      header = client.header
      param[:header].each do |h|
        k, v = h.split(": ")
        header[k] = v
      end
      header
    end
Request header Hash
 Merges default client headers with command line headers (-H or --header)