Why is first HttpClient.PostAsync call extremely slow in my C# winforms app? : <p>I have an httpclient like this : </p>

<pre><code>var client = new HttpClient();
</code></pre>

<p>I post to it like this:</p>

<pre><code>var result = client.PostAsync(
                endpointUri,
                requestContent);
</code></pre>

<p>And get the response like this:</p>

<pre><code>HttpResponseMessage response = result.Result;
</code></pre>

<p>I understand this call will block the thread, thats how its supposed to work (just building a tool for myself, no async threads needed)</p>

<p>The first time I run this call, it takes about 2 minutes to get a result.  Meanwhile, if I do the exact same call elsewhere its done in 200ms.  Even if I hit google, it takes 2 minutes.  But, after the first call, as long as I keep the app open any additional calls are good.  Its just the first cal when I open the application.  What could be causing this?</p>
