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: resolverfile.go
    path of file: ./repos/scan4all/vendor/github.com/projectdiscovery/fastdialer/fastdialer
    
    the code of the file until where you have to start completion: package fastdialer

import (
	"bufio"
	"net"
	"os"
	"path/filepath"
	"strings"

	"github.com/dimchansky/utfbom"
)

func loadResolverFile() ([]string, error) {
	osResolversFilePath := os.ExpandEnv(filepath.FromSlash(ResolverFilePath))

	if env, isset := os.Look
    
func loadResolverFile() ([]string, error) {
	osResolversFilePath := os.ExpandEnv(filepath.FromSlash(ResolverFilePath))

	if env, isset := os.LookupEnv("RESOLVERS_PATH"); isset && len(env) > 0 {
		osResolversFilePath = os.ExpandEnv(filepath.FromSlash(env))
	}

	file, err := os.Open(osResolversFilePath)
	if err != nil {
		return nil, err
	}
	defer file.Close()

	var systemResolvers []string

	scanner := bufio.NewScanner(utfbom.SkipOnly(file))
	for scanner.Scan() {
		resolverIP := HandleResolverLine(scanner.Text())
		if resolverIP == "" {
			continue
		}
		systemResolvers = append(systemResolvers, net.JoinHostPort(resolverIP, "53"))
	}
	return systemResolvers, nil
}