code: func (c *RawBinaryClient) Replace(item *Item) MutateResponse {
  	if item == nil {
  		return NewMutateErrorResponse("", errors.New("item is nil"))
  	}
  
  	c.mutex.Lock()
  	defer c.mutex.Unlock()
  
  	if resp := c.sendMutateRequest(opReplace, item, true); resp != nil {
  		return resp
  	}
  
  	return c.receiveMutateResponse(opReplace, item.Key)
  }
docs: // See Client interface for documentation.