code: function _modifySDPforFixIssue(sdp) {
      var parsedSDP = transform.parse(sdp);
  
      parsedSDP.groups = parsedSDP.groups ? parsedSDP.groups : [];
      parsedSDP.groups.push({
          mids: 'sdparta_0',
          type: 'BUNDLE'
      });
  
      return transform.write(parsedSDP);
  }
docs: It's functions to fixed issue
  https://bugzilla.mozilla.org/show_bug.cgi?id=1377434