if m.handlers.hasAny(id) && !id.isTestHandler() {
			return fmt.Errorf("handler %v: %w", id.String(), ErrHandlerAlreadyExists)
		}

		m.handlers.single[id] = h
		return nil
	}
	subID := makeSubHandlerID(id, s)
	if m.handlers.hasSubhandler(subID) && !id.isTestHandler() {
		return fmt.Errorf("handler %v, subroute:%v: %w", id.String(), s, ErrHandlerAlreadyExists)
	}
	m.handlers.subSingle[subID] = h

func (c *Connection) Subroute(s string) *Subroute {
	if c == nil {
		return nil
	}
	return &Subroute{
		Connection: c,
		route:      s,
		subID:      makeSubHandlerID(0, s),
		trace:      c.trace.subroute(s),
	}
}

// Subroute adds a subroute to the subroute.
// The subroutes are combined with '/'.
func (c *Subroute) Subroute(s string) *Subroute {

		OutCapacity int

		// InCapacity is the output capacity.
		// If == 0 no input is expected
		InCapacity int
	}
)

type subHandlerID [32]byte

func makeSubHandlerID(id HandlerID, subRoute string) subHandlerID {
	b := subHandlerID(sha256.Sum256([]byte(subRoute)))
	b[0] = byte(id)
	b[1] = 0 // Reserved
	return b
}