Unity的WWW请求的几种方式解析

 private UnityWebRequest _uwr;

public WWW(string url)
        {
            _uwr = UnityWebRequest.Get(url);
            _uwr.SendWebRequest();
        }

 public WWW(string url, WWWForm form)
        {
            _uwr = UnityWebRequest.Post(url, form);
            _uwr.chunkedTransfer = false;
            _uwr.SendWebRequest();
        }

public WWW(string url, byte[] postData)
        {
            _uwr = new UnityWebRequest(url, UnityWebRequest.kHttpVerbPOST);
            _uwr.chunkedTransfer = false;
            UploadHandler formUploadHandler = new UploadHandlerRaw(postData);
            formUploadHandler.contentType = "application/x-www-form-urlencoded";
            _uwr.uploadHandler = formUploadHandler;
            _uwr.downloadHandler = new DownloadHandlerBuffer();
            _uwr.SendWebRequest();
        }

   public WWW(string url, byte[] postData, Dictionary<string, string> headers)
        {
            var verb = postData == null ? UnityWebRequest.kHttpVerbGET : UnityWebRequest.kHttpVerbPOST;
            _uwr = new UnityWebRequest(url, verb);
            _uwr.chunkedTransfer = false;
            UploadHandler formUploadHandler = new UploadHandlerRaw(postData);
            formUploadHandler.contentType = "application/x-www-form-urlencoded";
            _uwr.uploadHandler = formUploadHandler;
            _uwr.downloadHandler = new DownloadHandlerBuffer();
            foreach (var header in headers)
                _uwr.SetRequestHeader(header.Key, header.Value);
            _uwr.SendWebRequest();
        }