This token is used by clients to request that the server start a packet-pair experiment. It is also used by servers to indicate whether they will comply with the request.
This token MUST have a value of either 0 or 1.
If this token is not specified, a value of 0 MUST be assumed.
The syntax of the packet-pair-experiment token is defined as follows.
packet-pair-experiment = "packet-pair-experiment=" ("0" / "1")