How to make outbound call using in C#

We have a RingCentral C# SDK available: https://github.com/ringcentral/ringcentral-csharp

It shows usage as something like this (I am not a C# developer, so my code example below may not be correct, and I would recommend you ask any questions you have about using this SDK in the Github Issues for the repository:

//import RingCentral

using RingCentral;  //Initialize Ring Central Client var sdk = new SDK(     "your appKey",     "your appSecret",     "RingCentral apiServer",     "Application Name",     "Application Version");  var authResponse = sdk.Platform.Login(userName, extension, password, true);  var ringoutPostBodyJson = "{"from":{"phoneNumber":"","forwardingNumberId":""},"to":{"phoneNumber":""},"callerId":{"phoneNumber":""},"playPrompt":false,"country":{"id":""}}";
 var request = new Request("/restapi/v1.0/account/~/extension/~/ringout", ringoutPostBodyJson); 

var ringoutResponse = sdk.Platform.Post(request);