console.time([label])
启动可用于计算操作持续时间的定时器。定时器由唯一的 label 标识。调用 console.timeEnd() 时使用相同的 label 停止定时器并将经过的时间以合适的时间单位输出到 stdout。例如,如果经过时间为 3869ms,则 console.timeEnd() 显示 "3.869s"。
¥Starts a timer that can be used to compute the duration of an operation. Timers
are identified by a unique label. Use the same label when calling
console.timeEnd() to stop the timer and output the elapsed time in
suitable time units to stdout. For example, if the elapsed
time is 3869ms, console.timeEnd() displays "3.869s".