用自定义struct标签中的空格解组Json [重复]

I am attempting to unmarshal data in Golang and I'm finding a strange behaviour when some key of the Json object has an underscore (_) in it.

To give an example:

package main

import (
    "encoding/json"
    "fmt"
)

func main() {
    var jsonBlob = []byte(`{"name": "Quoll", "order": "Dasyuromorphia"}`)
    type Animal struct {
        Name  string `json: "name"`
        Order string  `json: "order"`
    }
    var animal Animal
    err := json.Unmarshal(jsonBlob, &animal)
    if err != nil {
        fmt.Println("error:", err)
    }
fmt.Printf("%+v", animal)
}

This runs wonderfully. However, if I change some key to include an underscore:

 var jsonBlob = []byte(`{"name": "Quoll", "order_": "Dasyuromorphia"}`)

And I wanted this to be included into Animal.Order, I am attempting:

type Animal struct {
    Name  string `json: "name"`
    Order string  `json: "order_"`
}

and I am failing miserably to read the data. How can I map arbirary keys to the element I want of my struct? Here's a link to the playground with the example.

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