当 performanceEntry.type 等于 'function' 时，则 performanceEntry.detail 属性将是列出计时函数的输入参数的 <Array>。
performanceEntry.type
'function'
performanceEntry.detail
When performanceEntry.type is equal to 'function', the performanceEntry.detail property will be an <Array> listing the input arguments to the timed function.