How to use HttpClient in C#

  private async void  getservertime()
        {
            string servertime = "0";//Global variables are used in actual application, and the incoming parameters cannot be used for ref out keywords            HttpClientHandler handler1 = new HttpClientHandler();
             = false;
            HttpClient httpClient1 = new HttpClient(handler1);
            ("user-agent", UserAgent);
            if (InternetGetConnectedState(0, 0) == false)
            {
                //Not connected to the Internet                servertime = "0";
                return ;
            }
             
            try
            {
                HttpResponseMessage  result  = await  ("/rest/?api=");
               
                if ()
                {
                    ();
                    string responseBodyAsText = await ();
                    JObject sertime = (responseBodyAsText);                  
                    servertime=sertime["data"]["t"].ToString();                 
                }
                    
                else
                {
                    servertime= "0";
                }
               
 
            }
            catch (HttpRequestException hre)
            {
                servertime = "0"; ;
            }
            ();
            ();
 
 
        }

    private string getservertime()
 
        {
            HttpClientHandler handler1 = new HttpClientHandler();
           
             = false;
            HttpClient httpClient1 = new HttpClient(handler1);
            ("user-agent", UserAgent);
            if (InternetGetConnectedState(0, 0) == false)
            {
              //Not connected to the Internet                return "0";
            }
             
            try
            {
                var task = ("/rest/?api=");
                ();
                if ()
                    ();
                else
                {
                    return "0";
                }
                HttpResponseMessage response = ;
 
                //   =  + " " +  + ;
 
                var result = ();
                string responseBodyAsText = ;
 
                JObject sertime = (responseBodyAsText);
                ();
                ();
                return (sertime["data"]["t"].ToString());
 
 
            }
            catch (HttpRequestException hre)
            {
                ();
            }
            ();
            ();
            return "0";
 
          
        }

HttpClient client = new HttpClient();
//Add user identity authentication = new AuthenticationHeaderValue("Basic", Convert.ToBase64String(Encoding.($"{"account"}:{"password"}")));

HttpContent httpContent = new StringContent((), Encoding.UTF8);
 = new MediaTypeHeaderValue("application/json");

Uri url = new Uri("Request Link");
//httpContent is the Json data carried by the requestvar msg = (url, httpContent).().Result;

 HttpClient client = new HttpClient();
 //Add user identity authentication  = new AuthenticationHeaderValue("Basic", Convert.ToBase64String(Encoding.($"{"account"}:{"password"}")));
 
Uri url = new Uri("Request Link");
var msg = (url).().Result;