Issue uploading files (sync) #742

Error: System.Net.WebException: Request was cancelled. ---> System.IO.IOException: Cannot close the stream until all bytes are written
  --- End of inner exception stack trace ---
  at System.Net.WebConnectionStream.Close () [0x00183] in /private/tmp/source-mono-mac-4.0.0-branch-c5sr3/bockbuild-mono-4.0.0-branch/profiles/mono-mac-xamarin/build-root/mono-4.0.3/mcs/class/System/System.Net/WebConnectionStream.cs:821 
  at System.IO.Stream.Dispose () [0x00000] in /private/tmp/source-mono-mac-4.0.0-branch-c5sr3/bockbuild-mono-4.0.0-branch/profiles/mono-mac-xamarin/build-root/mono-4.0.3/external/referencesource/mscorlib/system/io/stream.cs:260 
  at RestSharp.Http.WriteRequestBody (System.Net.HttpWebRequest webRequest) [0x00000] in <filename unknown>:0 
  at RestSharp.Http.PostPutInternal (System.String method) [0x00000] in <filename unknown>:0 
  at RestSharp.Http.AsPost (System.String httpMethod) [0x00000] in <filename unknown>:0 
  at RestSharp.RestClient.DoExecuteAsPost (IHttp http, System.String method) [0x00000] in <filename unknown>:0 
  at RestSharp.RestClient.Execute (IRestRequest request, System.String httpMethod, System.Func`3 getResponse) [0x00000] in <filename unknown>:0 

using System;
using RestSharp;
using RestSharp.Extensions;
using System.IO;

namespace UploadTest
{
    class MainClass
    {
        public static void Main (string[] args)
        {
            var client = new RestClient("http://petstore.swagger.io/v2/");
            var request = new RestRequest("pet/{petId}/uploadImage", Method.POST);
            request.AddUrlSegment("petId", "2"); // replaces matching token in request.Resource

            FileStream stream = new FileStream ("/var/tmp/1.txt", FileMode.Open);

            var fileParam = FileParameter.Create("file", stream.ReadAsBytes(), Path.GetFileName(((FileStream)stream).Name));
            request.AddFile(fileParam.Name, fileParam.Writer, fileParam.FileName, fileParam.ContentType);
            // execute the request
            IRestResponse response = client.Execute(request);

            if (response.ErrorException != null)
            {
                Console.WriteLine("Error: " + response.ErrorException);
            }

            Console.WriteLine ("content=" + response.Content);
        }
    }
}