func (s *Store) Set(key, value string) error {
	s.mu.Lock()
	defer s.mu.Unlock()
	s.m[key] = value
	return nil
}
Set sets the value for the given key.
package store
import (
	"log"
	"os"
	"sync"
)
type Store struct {
	mu sync.RWMutex
	m  map[string]string  
	logger *log.Logger
}
func New() *Store {
	return &Store{
		m:      make(map[string]string),
		logger: log.New(os.Stderr, "[store] ", log.LstdFlags),
	}
}
func (s *Store) Open() error {
	s.logger.Println("store opened")
	return nil
}
func (s *Store) Close() error {
	return nil
}
func (s *Store) Get(key string) (string, error) {
	s.mu.RLock()
	defer s.mu.RUnlock()
	return s.m[key], nil
}