The routine FMT_TIMER is like FMT_TIM, except that FMT_TIMER is a
procedure which prints the first and last time in the index structure:
IDL> fmt_timer, index
(first, last) = '16-DEC-91 02:29:40', '16-DEC-91 02:29:40'
In this case, the index structure was a scalar, so the first and last
times are the same. The times can be returned in optional output
variables:
IDL> fmt_timer, index, t1, t2
The t1 and t2 are string variables which can be used in calls to
other routines (such as PLOT_GOES, for example).