code: func (b *FastLogStore) Get(k []byte) ([]byte, error) {
  	b.mu.RLock()
  	defer b.mu.RUnlock()
  	if b.closed {
  		return nil, ErrClosed
  	}
  	if val, ok := b.kvm[string(k)]; ok {
  		return val, nil
  	}
  	return nil, ErrKeyNotFound
  }
docs: // Get is used to retrieve a value from the k/v store by key