同时使用xml.Name和[] xml.Attr时属性重复

When I use a struct like

type MyStruct struct {
    XMLName xml.Name
    Attrs []xml.Attrs `xml:",attr,any"`
}

The Namespace taken from the xmlns-attribute is both an attribute in Attrs and the value of XMLName.Space. That is unfortunate, because I'd expect, that Attrs only contains only attributes, that are not handled elsewhere

Even worse, when I marshal and unmarshal an XML I'd expect to get the same XML. Instead I get something, that looks broken. xmlns is doubled

package main

import (
    "encoding/xml"
    "fmt"
)


func main() {
    var Foo struct {
        XMLName xml.Name `xml:""`
        Attr []xml.Attr `xml:",attr,any"`
    } = struct {
        XMLName xml.Name `xml:""`
        Attr []xml.Attr `xml:",attr,any"`
    }{}

    str := `
<foo xmlns="bar"/>
    `

    fmt.Println(str)
    xml.Unmarshal([]byte(str), &Foo)
    b, _ := xml.Marshal(&Foo)
    fmt.Println(string(b))
}

https://play.golang.org/p/ulWy-Paha2

Results in

<foo xmlns="bar"/>

<foo xmlns="bar" xmlns="bar"></foo>

How can I avoid this? Is there's a way to tell the decoder to simply ignore certain attributes completely?