How to get the value of a key which contains unicode code point in a JSON?

I'm trying to build a program that extract data from a JSON and put it into a custom struct. The JSON contains keys like "foo\u00a0", so I can't just use Unmarshal. I tried to use struct tags and it worked perfectly for "regular" tag but not when I use format like \u....

I tried with this:

package main

import (
        "encoding/json"
        "fmt"
)

type MyStruct struct {
        x string `json:"foobar\u0062"`
        Name string `json:"Username"`
}

func main() {
        data := []byte(`{"foobar\u0062": "some value", "Username": "xxx"}`)

        var ms MyStruct
        err := json.Unmarshal(data, &ms)
        if err != nil {
                panic(err)
        }

        fmt.Println(ms.x)
        fmt.Println(ms.Name)
}

In the example above, the key Username in the JSON is accessible with the field Name of the struct ms. That's not the case for the key foobar\u0062.

Why? How can I get the value of foobar\u0062, which is "some value" in that case ?

The struct field x has a json tag but is not exported. If you make it X instead (or anything starting with an upper case) then this code should work.

The high unicode codepoint is unrelated.

See Exported Names.