code: func NewMux() *Mux {
  	mux := &Mux{tree: &node{}, pool: &sync.Pool{}}
  	mux.pool.New = func() interface{} {
  		return NewRouteContext()
  	}
  	return mux
  }
docs: // NewMux returns a newly initialized Mux object that implements the Router
  // interface.