HttpClient: The uri string is too long
<p>Given the following attempt to post data to a web service that generates PDF files, <strong><a href="https://www.html2pdfrocket.com/" rel="noreferrer">PDF rocket</a></strong> (<em>which is awesome by the way</em>).</p>

<p>I get the error <strong>Invalid URI: The uri string is too long</strong><br>
<em>Why would anyone impose an arbitrary limit on <code>POST</code>ed data?</em></p>

<pre><code>using (var client = new HttpClient())
{
    // Build the conversion options
    var options = new Dictionary&lt;string, string&gt;
    {
        { "value", html },
        { "apikey", ConfigurationManager.AppSettings["pdf:key"] },
        { "MarginLeft", "10" },
        { "MarginRight", "10" }
    };

    // THIS LINE RAISES THE EXCEPTION
    var content = new FormUrlEncodedContent(options);

    var response = await client.PostAsync("https://api.html2pdfrocket.com/pdf", content);
    var result = await response.Content.ReadAsByteArrayAsync();
    return result;
}
</code></pre>

<p>I receive this rediculous error.</p>

<pre><code> {System.UriFormatException: Invalid URI: The Uri string is too long.
   at System.UriHelper.EscapeString
   at System.Uri.EscapeDataString
   at System.Net.Http.FormUrlEncodedContent.Encode
   at System.Net.Http.FormUrlEncodedContent.GetContentByteArray
</code></pre>

<p>This reminds me of <code>640k</code> ought to be enough... I mean <em>really?</em></p>