将正文添加到与 azure 服务 mgmt api 一起使用的 HttpWebRequest

我将如何添加到 HttpWebRequest 的正文？

身体需要由以下部分组成

<?xml version="1.0" encoding="utf-8"?>
<ChangeConfiguration xmlns="http://schemas.microsoft.com/windowsazure">
   <Configuration>base-64-encoded-configuration-file</Configuration>
   <TreatWarningsAsError>true|false</TreatWarningsAsError>
   <Mode>Auto|Manual</Mode>
</ChangeConfiguration>

任何帮助深表感谢

byte[] buf = Encoding.UTF8.GetBytes(xml);

request.Method = "POST";
request.ContentType = "text/xml";
request.ContentLength = buf.Length;
request.GetRequestStream().Write(buf, 0, buf.Length);

var HttpWebResponse = (HttpWebResponse)request.GetResponse();