5 val startCPUTimer: unit -> cpu_timer
6 val checkCPUTimer: cpu_timer -> {usr: Time.time, sys: Time.time, gc: Time.time}
7 val totalCPUTimer: unit -> cpu_timer
8 val startRealTimer: unit -> real_timer
9 val checkRealTimer: real_timer -> Time.time
10 val totalRealTimer: unit -> real_timer