update man page around start timestamps

A means to measure network responsiveness and throughput

Brought to you by: rjmcmahon

Milestone: 1.0

Status: accepted

Owner: Robert McMahon

Labels: None

Updated: 2022-09-06

Created: 2022-09-06

Private: No

Add man page information about how the start timestamps get initialized, e.g. when using trip-times