OkHttp请求很慢

Question

我使用OkHttp3。有时，API调用花费的时间比预期的要长，最多10秒。下次相同的通话可能要花几毫秒。

这是我的客户

private HttpClient() {
    OkHttpClient.Builder builder = new OkHttpClient.Builder();
    httpLoggingInterceptor = new HttpLoggingInterceptor(new HttpLoggingInterceptor.Logger() {
        @Override
        public void log(String message) {
            Log.e(TAG, message);
        }
    });
    if (BuildConfig.DEBUG_VERSION.equals(BuildConfig.VERSION_NAME)) {
        httpLoggingInterceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
    } else {
        httpLoggingInterceptor.setLevel(HttpLoggingInterceptor.Level.BASIC);
    }
    retryRequestInterceptor = new Interceptor() {
        @Override
        public Response intercept(Chain chain) throws IOException {
            Request request = chain.request();
            Response response = chain.proceed(request);

            int retryCode = 429; //retry request if this code received
            int tryCount = 0;
            int maxLimit = 1;

            while (response.code() == retryCode && tryCount < maxLimit) {
                Log.e(TAG, "Request failed, got " + response.code() + ". Retrying");
                tryCount++;
                response = chain.proceed(request);
            }
            return response;
        }
    };
    cache = new Cache(AppContext.getContext().getCacheDir(), cacheSize);
    client = buildClient(builder);
    request = new Request.Builder()
            .addHeader("Content-Type", "application/vnd.api+json");
    String versionName = BuildConfig.VERSION_NAME;
    int versionCode = BuildConfig.VERSION_CODE;
    if (versionCode < 0) {
        versionName = versionName.replaceFirst(String.valueOf(versionCode), "0-dev");
    }
    request.header("User-Agent", "NTR/" + String.valueOf(versionName));
}

private OkHttpClient buildClient(OkHttpClient.Builder builder) {
    builder.addInterceptor(httpLoggingInterceptor);
    builder.addInterceptor(retryRequestInterceptor);
    builder.cache(cache);
    return builder.build();
}

public static HttpClient getInstance() {
    if (instance == null) {
        instance = new HttpClient();
    }
    return instance;
}

我添加了HttpLoggingInterceptor并得到了

12-30 05:34:41.342  2400 10846 E DEBUG   : 0.001 connectionAcquired
12-30 05:34:41.353  2400 10846 E DEBUG   : 0.013 requestHeadersStart
12-30 05:34:41.354  2400 10846 E DEBUG   : 0.014 requestHeadersEnd
12-30 05:34:41.354  2400 10846 E DEBUG   : 0.014 requestBodyStart
12-30 05:34:41.355  2400 10846 E DEBUG   : 0.014 requestBodyEnd
12-30 05:34:41.358  2400 10846 E DEBUG   : 0.017 responseHeadersStart
12-30 05:34:45.435  2400 10846 E DEBUG   : 4.095 responseHeadersEnd

总是在头开始和结束之间出现延迟。

为什么会发生？