Remove AllowWriteStreamBuffering=false

Relates #2909

 AllowWriteStreamBuffering=false also needs to set the Content-Length header value or enable Transfer-Encoding: chunked. Both approaches require further benchmarking and investigation to understand if such a change is useful/viable.

Author: russcam

src/Elasticsearch.Net/Connection/HttpConnection.cs

@@ -60,7 +60,6 @@ protected virtual HttpWebRequest CreateWebRequest(RequestData requestData)
 			request.Accept = requestData.Accept;
 			request.ContentType = requestData.ContentType;
 			request.MaximumResponseHeadersLength = -1;
-			//request.AllowWriteStreamBuffering = false;
 			request.Pipelined = requestData.Pipelined;
 
 			if (requestData.HttpCompression)