title: Epplus get the column header
body: <p>I would like to understand how to get the column letter using Epplus. I know that Address will return the column letter and row number and FullAddress will add the sheet name but I don't see an object for just the column letter.</p>
  
  <pre><code>?sheet.Cells[index2, index3].Address
  "J2"
  
  ?sheet.Cells[index2, index3].FormulaR1C1
  ""
  
  ?sheet.Cells[index2, index3].FullAddress
  "'Sheet1'!J2"
  
  ?sheet.Cells[index2, index3].FullAddressAbsolute
  "'Sheet1'!$J$2"
  
  ?sheet.Cells[index2, index3].Rows
  </code></pre>