7.2.124 time-interests

(time-interests deltatime initial prefix [suffix])

Indicates that all interest-related messages, when separated by at least deltatime seconds of real time, should be preceded by the string prefix and followed by suffix; the first message is preceded by initial. All three are printf format strings, whose argument is the current clock time (in seconds) on that stream. A deltatime of zero timestamps every message. Typical usage:
(time-interests .1 (set-clock %g) (sleep-until %g)) or
(time-interests .1 (set-clock %g) "(sleep-until %g) (progn (set-clock %g)" ")") or
(time-interests .1 "(set-clock %g)" "(if (> 0 (sleep-until %g)) (" "))".