private void Start()
    {
        StartCoroutine(_cloudVrClient.LoadContentsList(this,
                                                       (contents) => {
            if (contents == null)
            {
                Debug.Log("No content exists.");
                return;
            }

            _title.text       = contents[0].title;
            _description.text = contents[0].description;
            StartCoroutine(contents[0].LoadThumbnail(this, 0, (index, thumbnail) => {
                _thumbnail.texture = thumbnail;
            }, (errorCode, error) => {
                Debug.Log(string.Format("LoadThumbnail failed : {0} : {1}", errorCode.ToString(), error));
            }));

            for (int i = 0; i < Mathf.Min(_screenshots.Length, contents[0].screenshots.Length); i++)
            {
                StartCoroutine(contents[0].LoadScreenshot(this, i, (index, screenshot) => {
                    _screenshots[index].texture = screenshot;
                }, (errorCode, error) => {
                    Debug.Log(string.Format("LoadScreenshot {3} failed : {0} : {1}", errorCode.ToString(), error, i));
                }));
            }
        },
                                                       (errorCode, error) => {
            Debug.Log(string.Format("LoadContentsList failed : {0} : {1}", errorCode.ToString(), error));
        }
                                                       ));

        StartCoroutine(_cloudVrClient.GetTrackers(this,
                                                  (trackers) => {
            foreach (var tracker in trackers)
            {
                Debug.Log(string.Format("Tracker : {0} : {1}", tracker.userID, tracker.trackerID));
            }
        },
                                                  (errorCode, error) => {
            Debug.Log(string.Format("GetTrackers failed : {0} : {1}", errorCode.ToString(), error));
        }
                                                  ));
    }
    private void Start()
    {
        StartCoroutine(_cloudVrClient.LoadContentsList(this,
                                                       (contents) => {
            if (contents == null)
            {
                Debug.Log("No content exists.");
                return;
            }

            _title.text       = contents[0].title;
            _description.text = contents[0].description;
            StartCoroutine(contents[0].LoadThumbnail(this, 0, (index, thumbnail) => {
                _thumbnail.texture = thumbnail;
            }, (errorCode, error) => {
                Debug.Log(string.Format("LoadThumbnail failed : {0} : {1}", errorCode.ToString(), error));
            }));

            for (int i = 0; i < Mathf.Min(_screenshots.Length, contents[0].screenshots.Length); i++)
            {
                StartCoroutine(contents[0].LoadScreenshot(this, i, (index, screenshot) => {
                    _screenshots[index].texture = screenshot;
                }, (errorCode, error) => {
                    Debug.Log(string.Format("LoadScreenshot {3} failed : {0} : {1}", errorCode.ToString(), error, i));
                }));
            }

            StartCoroutine(contents[0].RequestLinkage(this, (linkage) => {
                Debug.Log(string.Format("Linkage created : {0}:{1}", linkage.host, linkage.port.ToString()));
            }, (errorCode, error) => {
                Debug.Log(string.Format("Linkage creation failed : {0} : {1}", errorCode.ToString(), error));
            }));
        },
                                                       (errorCode, error) => {
            Debug.Log(string.Format("LoadContentsList failed : {0} : {1}", errorCode.ToString(), error));
        }
                                                       ));
    }