A simple NTP client. Keeps the Particle Photon Time synced to NTP. This should not be used for high precision time keeping. The Particle Photon Time is only one second resolution and hardware limitations prevent high accuracy setting. So the system time shouldn't be used for anything that needs more than accuracy to a large fraction of a second.
There is an interface that will return the time to millisecond resolution. Accuracy of that interface is primarily dependent on internet latency.
NtpTime uses one of the Photon's software timers.