Marshaling does not agree with json.Encoder

[barkyq]

The marshaling uses some form of string escaping (via strconv.Quote), which does not preserve the underlying UTF-8 representation.
This causes signature verification to fail in nbd-wtf/go-nostr#28 (an incompatibility with clients written in other languages).

Is it possible to add an option to disable string escaping? This option is present in the standard encoding/json package, see https://pkg.go.dev/encoding/json#Marshal, SetEscapeHTML.

Minimal working example:

import (
	"encoding/json"
	"fmt"
	"github.com/valyala/fastjson"
)
func main() {
	a := fastjson.Arena{}
	s := string(rune(142)) + "\n"
	val := a.NewString(s)
	buf1 := val.MarshalTo(nil)
	buf2, _ := json.Marshal(s)
	fmt.Printf("%x\n", buf1)
	fmt.Printf("%x\n", buf2)
}

returns:

225c75303038655c6e22
22c28e5c6e22