@Override
  public JsonObjectBuilder getJsonObjectBuilder() {
    return super.getJsonObjectBuilder()
        .add("bytesSent", this.bytesSent)
        .add("bytesReceived", this.bytesReceived)
        .add("selectedCandidatePairId", this.selectedCandidatePairId)
        .add("localCertificateId", this.localCertificateId)
        .add("remoteCertificateId", this.remoteCertificateId);
  }
RTCTransportStats, with attributes bytesSent, bytesReceived, rtcpTransportStatsId, selectedCan
KITE-Framework/src/main/java/org/webrtc/kite/stats/rtc/RTCTransportStats.java