您可以通过ObsClient.DeleteBucketCors删除桶的跨域规则。以下代码展示了如何删除跨域规则：

// 引入依赖包
import (
       "fmt"
       "obs"
)

var ak = "*** Provide your Access Key ***"
var sk = "*** Provide your Secret Key ***"
var endpoint = "https://your-endpoint"

// 创建ObsClient结构体
var obsClient, _ = obs.New(ak, sk, endpoint)

func main() {
       output, err := obsClient.DeleteBucketCors("bucketname")
       if err == nil {
              fmt.Printf("RequestId:%s\n", output.RequestId)
       } else if obsError, ok := err.(obs.ObsError); ok {
              fmt.Printf("Code:%s\n", obsError.Code)
              fmt.Printf("Message:%s\n", obsError.Message)
       }
}