Delay calculated against wallclock
The delay in src/rist.c is calculated against wallclock/systemtime/etc. while the spec states "NTP timestamp: 64 bitsIndicates the wallclock time when this report was sent. The most significant 32 bits on thisfield indicate the number of seconds since 0h UTC on January 1900, and the least significant 32 bits indicate the fraction of the second. On a system that has no notion of wallclock time but does have some system-specific clock such as "System uptime", a sender mayuse that clock as a reference to calculate relative NTP timestamps. A sender that has no notion of wallclock or elapsed time may set the NTP timestamp to zero."