title: Creating a new ExcelPackage using Stream from IFormFile not working
body: <p>I am trying to create an <code>ExcelPackage</code> using EPPlus by uploading an <code>IFormFile</code>.  It sounds really simple and all the samples I find are doing what I am doing, but mine doesn't seem to work.</p>
  <p>I am using .NET Core and I've verified that the file exists and that it is creating the stream correctly.  I was using <code>ClosedXml</code> with the same file and it created the <code>XLWorksheet</code> correct so I know the stream is correct. The issue is when I try to set the worksheet in the below code, the <code>package.Workbook.Worksheets</code> contains zero entries.  In other words, <code>package.Workbook.Worksheets.Count = 0</code>.  Would someone be able to tell me what I'm missing?  Like I said, I've been all over the internet and everyone says this should work, but it doesn't seem to work for me.</p>
  <p>Thanks</p>
  <pre class="lang-cs prettyprint-override"><code>[HttpPost(&quot;Excel&quot;]
  public IActionResult UploadExcel([FromForm]IFormFile file)
  {
      var stream = file.OpenReadStream();
      using (ExcelPackage package = new ExcelPackage(stream))
      {
          var worksheet = package.Workbook.Worksheets[0];
      }
  }
  </code></pre>
  <p>I would expect <code>package.Workbook.Worksheets</code> to contain 1 worksheet with the data from the excel file that is passed in.  I don't receive any errors, there is just no worksheet.</p>