code: func (mx *Mux) handle(method methodTyp, pattern string, handler http.Handler) *node {
  	if len(pattern) == 0 || pattern[0] != '/' {
  		panic(fmt.Sprintf("chi: routing pattern must begin with '/' in '%s'", pattern))
  	}
  
  	// Build the final routing handler for this Mux.
  	if !mx.inline && mx.handler == nil {
  		mx.buildRouteHandler()
  	}
  
  	// Build endpoint handler with inline middlewares for the route
  	var h http.Handler
  	if mx.inline {
  		mx.handler = http.HandlerFunc(mx.routeHTTP)
  		h = Chain(mx.middlewares...).Handler(handler)
  	} else {
  		h = handler
  	}
  
  	// Add the endpoint to the tree and return the node
  	return mx.tree.InsertRoute(method, pattern, h)
  }
docs: // handle registers a http.Handler in the routing tree for a particular http method
  // and routing pattern.