anchor.diff:     (bench nil) => 0.00 nanoseconds
      (bench (make-hash-table)) => 247.03 nanoseconds"
     (declare (ignore max-samples min-sample-time timeout overhead))
  -  `(print-time (benchmark ,form ,@args) *trace-output*))
  +  `(progn (print-time (benchmark ,form ,@args) *trace-output*)
  +          (values)))
   
   (defmacro benchmark (form &rest args &key max-samples min-sample-time timeout overhead)
     "Execute BODY multiple times to accurately measure its execution time in
  
positive.code:     (declare (ignore _))
      (max 0.0d0 (local-time:timestamp-difference t1 t0))))
  
  (defvar *default-overhead* (benchmark nil :timeout 2.0 :overhead 0))
  
negative.code:           until (or (local-time:timestamp>= (local-time:now) tmax)
                      (and (not (null max-samples))
                           (>= number-of-samples max-samples))))
      (- (/ (reduce #'+ samples)
            (coerce number-of-samples 'single-float))
         overhead)))
  
  (defun sample-execution-time-of-thunk (thunk min-sample-time)
  