go build 编译问题

[ritech]

编译出现bug ./tcping.go:22:33: error: reference to undefined field or method ‘Microseconds’ var duration = float64(endTime.Microseconds()) / 1000.0 ^ ./tcping.go:24:16: error: incompatible type for return value 2 (cannot use type float64 as type float32) return true, duration ^