You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: types.go
    path of file: ./repos/buildkit/vendor/github.com/golang-jwt/jwt/v4
    
    the code of the file until where you have to start completion: package jwt

import (
	"encoding/json"
	"fmt"
	"math"
	"refl
    
func (s ClaimStrings) MarshalJSON() (b []byte, err error) {
	// This handles a special case in the JWT RFC. If the string array, e.g. used by the "aud" field,
	// only contains one element, it MAY be serialized as a single string. This may or may not be
	// desired based on the ecosystem of other JWT library used, so we make it configurable by the
	// variable MarshalSingleStringAsArray.
	if len(s) == 1 && !MarshalSingleStringAsArray {
		return json.Marshal(s[0])
	}

	return json.Marshal([]string(s))
}