RTCStats.timestamp
  The timestamp property of the
  RTCStats dictionary is a DOMHighResTimeStamp object
  specifying the time at which the data in the object was sampled.
For reports related to RTCP packets, for instance, this indicates the time at which the data covered by the statistics was received at the corresponding endpoint.
The time is given in milliseconds elapsed since the UNIX epoch (the first moment of January 1, 1970, UTC).
Value
  A DOMHighResTimeStamp value indicating the time at which the activity
  described by the statistics in this object was recorded, in milliseconds elapsed since
  the beginning of January 1, 1970, UTC. This should be accurate to within a few
  milliseconds but may not be entirely precise, either because of hardware or operating
  system limitations or because of fingerprinting protection in the form of reduced clock
  precision or accuracy.
Specifications
No specification found
No specification data found for api.RTCStats.timestamp.
Check for problems with this page or contribute a missing spec_url to mdn/browser-compat-data. Also make sure the specification is included in w3c/browser-specs.
Browser compatibility
No compatibility data found for api.RTCStats.timestamp.
Check for problems with this page or contribute missing data to mdn/browser-compat-data.