queryDNSTXT may produce wrong DKIM record using the default resolver

I am reading the code and found that queryDNSTXT may produce the wrong txt record using the default resolver net.LookupTXT

dkim/query.go line 88 wrote that

// Long keys are split in multiple parts
txt := strings.Join(txts, "")

but the default resolve has already joined the txt record with multiple line.

// Multiple strings in one TXT record need to be
// concatenated without separator to be consistent
// with previous Go resolver.
n := 0
for _, s := range txt.TXT {
    n += len(s)
}
txtJoin := make([]byte, 0, n)
for _, s := range txt.TXT {
    txtJoin = append(txtJoin, s...)
}
if len(txts) == 0 {
    txts = make([]string, 0, 1)
}
txts = append(txts, string(txtJoin))

So, if there are multiple records along with DKIM record. It will produce a wrong DKIM record, and the following parsePublicKey will fail

emersion / go-msgauth

queryDNSTXT may produce wrong DKIM record using the default resolver #54