request.GetResponse（）在vb.net中给出了“操作已超时”

在vb.net中获取POST方法web请求的响应时，我遇到了一个问题，GET请求工作正常并获得了响应，而同样的请求在C中工作正常，步骤如下。那么，有人能帮我解决这个问题吗

这里Url是一个弹性搜索引擎，postData变量中的数据是一个json字符串，响应也是一个json字符串

Dim请求作为System.Net.HttpWebRequest=System.Net.HttpWebRequest.CreateHOSTIP:9200/es5078_1/_search？pretty=true

    request.Method = "POST"
    Dim postData As String = CGeneral.gstrMsgNC(236)
    request.ContentType = "application/x-www-form-urlencoded"
    request.ContentLength = postData.Length
    request.Timeout = 100000

    Dim writer As StreamWriter = New StreamWriter(request.GetRequestStream())
    writer.Write(postData)
    request.Expect = ""
    request.AllowAutoRedirect = True
    request.AllowWriteStreamBuffering = True

    Dim response As System.Net.HttpWebResponse = request.GetResponse()

    Dim responseReader As StreamReader = New StreamReader(response.GetResponseStream())
    Dim result As String = responseReader.ReadToEnd()

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我也有类似的问题，但在C语言中。在向ElasticSearch发送数百个并行的索引POST请求时，我得到System.Net.WebException，其中一部分操作已超时System.IO.Stream GetRequestStream。