code: func (b *BigIP) CreateVirtualServer(name, destination, mask, pool string, port int) error {
  	subnetMask := cidr[mask]
  
  	if strings.Contains(mask, ".") {
  		subnetMask = mask
  	}
  
  	config := &VirtualServer{
  		Name:        name,
  		Destination: fmt.Sprintf("%s:%d", destination, port),
  		Mask:        subnetMask,
  		Pool:        pool,
  	}
  
  	return b.post(config, uriLtm, uriVirtual)
  }
docs: // CreateVirtualServer adds a new virtual server to the BIG-IP system. <mask> can either be
  // in CIDR notation or decimal, i.e.: "24" or "255.255.255.0". A CIDR mask of "0" is the same
  // as "0.0.0.0".