code: func (cli *Client) BuildCancel(ctx context.Context, id string) error {
  	query := url.Values{}
  	query.Set("id", id)
  
  	serverResp, err := cli.post(ctx, "/build/cancel", query, nil, nil)
  	ensureReaderClosed(serverResp)
  	return err
  }
docs: // BuildCancel requests the daemon to cancel ongoing build request