在Golang中从HTML中提取文本内容

在Golang中从字符串中提取内部子串的最佳方法是什么？

输入:

"Hello 
 this is paragraph 
 this is junk 
 this is paragraph 2 
 this is junk 2"

输出:

"this is paragraph \n
 this is paragraph 2"

是否有任何字符串包/库已经做了类似的事情？

package main

import (
    "fmt"
    "strings"
)

func main() {
    longString := "Hello world 
 this is paragraph 
 this is junk 
 this is paragraph 2 
 this is junk 2"

    newString := getInnerStrings("
", "
", longString)

    fmt.Println(newString)
   //output: this is paragraph \n
    //        this is paragraph 2

}
func getInnerStrings(start, end, str string) string {
    //Brain Freeze
        //Regex?
        //Bytes Loop?
}

谢谢