text:         messageString = (
              'REGISTER sip:example.com SIP/2.0\r\n'
              'To: sip:null-%00-null@example.com\r\n'
              'From: sip:null-%00-null@example.com;tag=839923423\r\n'
              'Max-Forwards: 70\r\n'
              'Call-ID: escnull.39203ndfvkjdasfkq3w4otrq0adsfdfnavd\r\n'
              'CSeq: 14398234 REGISTER\r\n'
              'Via: SIP/2.0/UDP host5.example.com;branch=z9hG4bKkdjuw\r\n'
              'Contact: <sip:%00@host5.example.com>\r\n'
              'Contact: <sip:%00%00@host5.example.com>\r\n'
              'L:0\r\n'
              '\r\n'
          )
  