'Add a question to the message.
@param qname: the question name
@type qname: dns.name.Name
@param rdtype: the question rdata type
@type rdtype: int
@param rdclass: the question rdata class
@type rdclass: int'

def add_question(self, qname, rdtype, rdclass=dns.rdataclass.IN):

    self._set_section(QUESTION)
    before = self.output.tell()
    qname.to_wire(self.output, self.compress, self.origin)
    self.output.write(struct.pack('!HH', rdtype, rdclass))
    after = self.output.tell()
    if (after >= self.max_size):
        self._rollback(before)
        raise dns.exception.TooBig
    self.counts[QUESTION] += 1
