To determine the number of bytes already sent, use the BytesSent property.
Uploading data to a server may result in a download from the server. For example, suppose your application uploads a POST request to a Web server. The resulting download will update BytesReceived and TotalBytesToReceive.
Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)