webrtc - RTCDataChannel not working iOS -

i'm using rtcdatachannel. messages i'm sending through channel not receiving @ other peer.

here code:

        let audioconstraint : rtcpair = rtcpair(key: "offertoreceiveaudio", value: "true")         let videoconstraint : rtcpair = rtcpair(key: "offertoreceivevideo", value: "true")         let dtlsconstraint : rtcpair = rtcpair(key: "dtlssrtpkeyagreement", value: "true")         let mediacontraints : rtcmediaconstraints = rtcmediaconstraints(mandatoryconstraints: [audioconstraint, videoconstraint], optionalconstraints: [ dtlsconstraint])          rtcpeerconnectionfactory.initializessl()         peerconnection = peerconnectionfactory.peerconnectionwithiceservers(servers, constraints: mediacontraints, delegate: self)          datachannels = peerconnection?.createdatachannelwithlabel(channelname,config: nil)         datachannels?.delegate = self           var message : nsdata = nsdata(base64encodedstring: "helloo")         var buffer : rtcdatabuffer = rtcdatabuffer(data: message, isbinary: true)         datachannels?.senddata(buffer) 

have resolved it? 1 of 2 peers should create data channel , other should attach received data channel object data channel object. initiator should create datachannel before sending offer. hope might helpful