code: func DefaultServiceConfig() ServiceConfig {
  	return ServiceConfig{
  		// Dependencies.
  		BackoffFactory: func() Backoff {
  			return &backoff.StopBackOff{}
  		},
  		RandFactory: rand.Int,
  
  		// Settings.
  		RandReader: rand.Reader,
  		Timeout:    1 * time.Second,
  	}
  }
docs: // DefaultServiceConfig provides a default configuration to create a new random
  // service by best effort.