Statistics of the network quality.
After joining the channel, the SDK triggers the
"network-quality" callback and provides the network quality ratings in this interface.
Downlink network quality rating of the user in terms of packet loss rate, average RTT, and jitter of the downlink network.
Uplink network quality rating of the user in terms of the transmission bitrate, packet loss rate, average RTT (Round-Trip Time) and jitter of the uplink network.