@rahuahua 类似这样子
```go
func (a *App) Handle(method string, group string, path string, handler Handler, mw ...Middleware) {

// First wrap handler specific middleware around this handler.
handler = wrapMiddleware(mw, handler)

// Add the application's general middleware to the handler chain.
handler = wrapMiddleware(a.mw, handler)

// The function to execute for each request.
h := func(w http.ResponseWriter, r *http.Request) {

// Pull the context from the request and
// use it as a separate parameter.
ctx := r.Context()

// Capture the parent request span from the context.
span := trace.SpanFromContext(ctx)

// Set the context with the required values to
// process the request.
v := Values{
TraceID: span.SpanContext().TraceID().String(),
Now: time.Now().UTC(),
}
ctx = context.WithValue(ctx, key, &v)

// Call the wrapped handler functions.
if err := handler(ctx, w, r); err != nil {
a.SignalShutdown()
return
}
}

finalPath := path
if group != "" {
finalPath = "/" + group + path
}
a.mux.Handle(method, finalPath, h)
}
```