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
^