How I would implement storing the record line with the storage object using FileHelpers

RecordStringConverter.cs

using System;
using FileHelpers;
using NUnit.Framework;

namespace FileHelpers.Tests.Converters
{
  [TestFixture]
  public class RecordStringConverter.cs
  {
    FileHelperEngine<UserRecord> engine = new FileHelperEngine<UserRecord>();

    [Test]
    public void Test();
    {
      string sampleData = 
@"123456;Phillip     ;Fry
098765;Turanga     ;Leela
110110;Bender     ;Rodriguez
INVALID ID FOR MY DATA SET;Zapp     ;Brannigan";
      
      UserRecord[] users = engine.ReadString(sampleData);
      
      foreach (var user in users)
      {
        int login;
        if (!int.TryParse(user.LoginId, out login))
        {
          Assert.AreEqual("INVALID ID FOR MY DATA SET;Zapp     ;Brannigan", user.RecordString) //NOTE the spaces
        }
      }
    }
    
    [DelimitedRecord(";")]
    private class UserRecord
    {
      [FieldTrim(TrimMode.Both)]
      public string LoginId;
      [FieldTrim(TrimMode.Both)]
      public string FirstName;
      [FieldTrim(TrimMode.Both)]
      public string LastName;

      //possible implementation
      //[RecordString]
      //public string RecordString;
    }
    
  }
}