code: func WithLocalEndpoint(e *model.Endpoint) TracerOption {
  	return func(o *Tracer) error {
  		if e == nil {
  			o.localEndpoint = nil
  			return nil
  		}
  		ep := *e
  		o.localEndpoint = &ep
  		return nil
  	}
  }
docs: // WithLocalEndpoint sets the local endpoint of the tracer.