code: func (d *DeferredDiscoveryRESTMapper) RESTMapping(gk schema.GroupKind, versions ...string) (m *meta.RESTMapping, err error) {
  	del, err := d.getDelegate()
  	if err != nil {
  		return nil, err
  	}
  	m, err = del.RESTMapping(gk, versions...)
  	if err != nil && !d.cl.Fresh() {
  		d.Reset()
  		m, err = d.RESTMapping(gk, versions...)
  	}
  	return
  }
docs: // RESTMapping identifies a preferred resource mapping for the
  // provided group kind.