code: func Init(d driver.Driver) *Storage {
  	// default driver is in memory
  	if d == nil {
  		d = driver.NewMemory()
  	}
  	return &Storage{
  		Driver: d,
  		Log:    func(_ string, _ ...interface{}) {},
  	}
  }
docs: // Init initializes a new storage backend with the driver d.
  // If d is nil, the default in-memory driver is used.