Modified Http.Sync.cs and Http.Async.cs to replace

ServicePointManager.Expect100Continue = false;

with

webRequest.ServicePoint.Expect100Continue = false;

The original version sets the default for future ServicePoints, not the
current ServicePoint. I don't think setting the global default here is a
great idea, and it doesn't affect the current ServicePoint which has
already been created.

Author: jeffa00

RestSharp/Http.Async.cs

@@ -443,7 +443,8 @@ private HttpWebRequest ConfigureAsyncWebRequest(string method, Uri url)
             }
 
             webRequest.AutomaticDecompression = DecompressionMethods.Deflate | DecompressionMethods.GZip | DecompressionMethods.None;
-            ServicePointManager.Expect100Continue = false;
+
+            webRequest.ServicePoint.Expect100Continue = false;
 
             if (Timeout != 0)
             {

RestSharp/Http.Sync.cs

@@ -254,7 +254,7 @@ private HttpWebRequest ConfigureWebRequest(string method, Uri url)
 #endif
             webRequest.PreAuthenticate = PreAuthenticate;
 
-            ServicePointManager.Expect100Continue = false;
+            webRequest.ServicePoint.Expect100Continue = false;
 
             AppendHeaders(webRequest);
             AppendCookies(webRequest);