code: func NewTokenProvider(opts ...TokenProviderOption) (*TokenProvider, error) {
  	provider := new(TokenProvider)
  	for _, opt := range opts {
  		err := opt(provider)
  		if err != nil {
  			return nil, err
  		}
  	}
  	return provider, nil
  }
docs: // NewTokenProvider builds a SAS claims-based security token provider