The totalPacketSendDelay property of the RTCOutboundRtpStreamStats dictionary represents the total time in seconds that packets have spent buffered locally before being transmitted.
The individual packet delay is the time between a packet being emitted from the RTP packetizer and it being handed over to the OS network socket. The individual delay is added to totalPacketSendDelay when packetsSent is incremented.
Note: The property is undefined for audio streams.
The delay in seconds, represented as a number.