code: func (c *Config) String() string {
  	if c == nil {
  		return "<nil>"
  	}
  	cc := sanitizedConfig(CopyConfig(c))
  	// Explicitly mark non-empty credential fields as redacted.
  	if cc.Password != "" {
  		cc.Password = "--- REDACTED ---"
  	}
  	if cc.BearerToken != "" {
  		cc.BearerToken = "--- REDACTED ---"
  	}
  	if cc.AuthConfigPersister != nil {
  		cc.AuthConfigPersister = sanitizedAuthConfigPersister{cc.AuthConfigPersister}
  	}
  
  	return fmt.Sprintf("%#v", cc)
  }
docs: // String implements fmt.Stringer and sanitizes sensitive fields of Config to
  // prevent accidental leaking via logs.