code: func (c *Coordinate) Update(coord *CoordinateEntry, q *WriteOptions) (*WriteMeta, error) {
  	r := c.c.newRequest("PUT", "/v1/coordinate/update")
  	r.setWriteOptions(q)
  	r.obj = coord
  	rtt, resp, err := requireOK(c.c.doRequest(r))
  	if err != nil {
  		return nil, err
  	}
  	defer resp.Body.Close()
  
  	wm := &WriteMeta{}
  	wm.RequestTime = rtt
  
  	return wm, nil
  }
docs: // Update inserts or updates the LAN coordinate of a node.