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: rss.go
    path of file: ./repos/v2/internal/reader/rss
    
    the code of the file until where you have to start completion: // SPDX-FileCopyrightText: Copyright The Miniflux Authors. All rights reserved.
// SPDX-License-Identifier: Apache-2.0

package rss // import "miniflux.app/v2/internal/reader/rss"

import (
	"encoding/xml"
	"html"
	"log/slog"
	"path"
	"strconv"
	"strings"
	"time"

	"miniflux.app/v2/internal/crypto"
	"miniflux.app/v2/internal/model"
	"miniflux.app/v2/in
    
func (r *rssItem) entryURL() string {
	if r.FeedBurnerLink != "" {
		return r.FeedBurnerLink
	}

	for _, link := range r.Links {
		if link.XMLName.Space == "http://www.w3.org/2005/Atom" && link.Href != "" && isValidLinkRelation(link.Rel) {
			return strings.TrimSpace(link.Href)
		}

		if link.Data != "" {
			return strings.TrimSpace(link.Data)
		}
	}

	// Specs: https://cyber.harvard.edu/rss/rss.html#ltguidgtSubelementOfLtitemgt
	// isPermaLink is optional, its default value is true.
	// If its value is false, the guid may not be assumed to be a url, or a url to anything in particular.
	if r.GUID.IsPermaLink == "true" || r.GUID.IsPermaLink == "" {
		return strings.TrimSpace(r.GUID.Data)
	}

	return ""
}