Sends a response to the client.

def Send(self,
           data,
           status=200,
           ctype="application/octet-stream",
           additional_headers=None,
           last_modified=0):
    """Sends a response to the client."""
    if additional_headers:
      additional_header_strings = [
          "%s: %s\r\n" % (name, val)
          for name, val in iteritems(additional_headers)
      ]
    else:
      additional_header_strings = []

    header = ""
    header += "HTTP/1.0 %s\r\n" % self.statustext[status]
    header += "Server: GRR Server\r\n"
    header += "Content-type: %s\r\n" % ctype
    header += "Content-Length: %d\r\n" % len(data)
    header += "Last-Modified: %s\r\n" % self.date_time_string(last_modified)
    header += "".join(additional_header_strings)
    header += "\r\n"

    self.wfile.write(header.encode("utf-8"))
    self.wfile.write(data)