我有一個奇怪的情況。我想application/json; charset=utf-8從 http 處理程序返回內容類型。func handleTest() http.HandlerFunc {    return func(w http.ResponseWriter, r *http.Request) {        if r.Header.Get("Accept") != "application/json" {            w.WriteHeader(http.StatusNotAcceptable)            return        }        w.WriteHeader(http.StatusOK)        w.Header().Set("Content-Type", "application/json; charset=utf-8")        json.NewEncoder(w).Encode(map[string]string{"foo": "bar"})    }}當我在單元測試中檢查這一點時，它是正確的。這個測試沒有失敗。func TestTestHandler(t *testing.T) {    request, _ := http.NewRequest(http.MethodGet, "/test", nil)    request.Header.Set("Accept", "application/json")    response := httptest.NewRecorder()    handleTest().ServeHTTP(response, request)    contentType := response.Header().Get("Content-Type")    if contentType != "application/json; charset=utf-8" {        t.Errorf("Expected Content-Type to be application/json; charset=utf-8, got %s", contentType)        return    }}但是當我嘗試使用 curl （和其他客戶端）時，它會顯示為text/plain; charset=utf-8.$ curl -H 'Accept: application/json' localhost:8080/test -v*   Trying 127.0.0.1:8080...* TCP_NODELAY set* Connected to localhost (127.0.0.1) port 8080 (#0)> GET /test HTTP/1.1> Host: localhost:8080> User-Agent: curl/7.68.0> Accept: application/json> * Mark bundle as not supporting multiuse< HTTP/1.1 200 OK< Date: Tue, 28 Dec 2021 13:02:27 GMT< Content-Length: 14< Content-Type: text/plain; charset=utf-8< {"foo":"bar"}* Connection #0 to host localhost left intact我用 curl、insomnia 和 python 試過這個。在所有 3 種情況下，內容類型都是text/plain; charset=utf-8.是什么導致了這個問題，我該如何解決？