Returns a Promise that resolves with an object of network stats:
latest field is a collection of statistics from the most recent time period. These statistics are updated approximately once every two seconds. You can poll the
getNetworkStats() method to continually read the current network performance.
worstVideoSendPacketLoss are what the names suggest: the worst packet loss number seen for a two-second period, during the current call.
threshold is an assessment of the current network quality, and can have the value
very-low. The threshold value is calculated from network stats averaged over an approximately 30-second rolling window. By default, we lower the bandwidth used for the call, when the network quality drops to
low, and we turn off the local camera when the network quality drops to
quality is a subjective calculation of the current network quality on a scale of 1-100, suitable for display in a user interface.