Start Time is the time from start of 1st request until the start of this request.
End Time is the time from start of 1st request until the end of this response.
Latency is the time from end of this request until the beginning of download of this response.
Response Time is the time from start of 1st request until the beginning of download of this response.
Duration is the time from start of this request until the end of this response.
K. Polanyi. Beacon Press, Boston, MA, 2nd Beacon paperback ed. edition, (2001)Originally published: New York : Farrar & Rinehart, 1944 and reprinted in 1957 by Beacon in Boston - Includes bibliographical references and index.