在go中，AuthFromMD总是期望authorization作为头名称。我怎么才能覆盖它。

package main

import (
    "fmt"
    "net/http"
)

func main() {
    client := &http.Client{}

    req, err := http.NewRequest("GET", "https://example.com", nil)
    if err != nil {
        fmt.Println("Error creating request:", err)
        return
    }

    req.Header.Set("authorization", "your_custom_value")

    resp, err := client.Do(req)
    if err != nil {
        fmt.Println("Error sending request:", err)
        return
    }
    defer resp.Body.Close()

    // 处理响应
    // ...
}