Examples:

/timestamps
By default, display the elapsed time in seconds with three places after the decimal point.
/timestamps?time=HH:mm:ss&appendLog
Display the system clock time and append the line from the log.
/timestamps?elapsed=HH:mm:ss.S&appendLog
Display the elapsed time and append the line from the log.
/timestamps?time=HH:mm:ss&elapsed=HH:mm:ss.S
Display both the system clock time and the elapsed time.
/timestamps?currentTime&time=HH:mm:ss
Display the current time on the Jenkins master.

< HTTP/1.1 302 Found
< Server: nginx/1.10.2
< Date: Tue, 10 Apr 2018 10:31:27 GMT
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< Connection: keep-alive
< X-Content-Type-Options: nosniff
< Access-Control-Allow-Origin: *
< Access-Control-Allow-Methods: GET, POST, PUT, DELETE
< Access-Control-Allow-Headers: Authorization
< Set-Cookie: JSESSIONID.10fc358a=node012rg8l3t0wed1579tpofuy89u1019.node0;Path=/;Secure;HttpOnly
< Expires: Thu, 01 Jan 1970 00:00:00 GMT