Customizando de forma flexível o nome das colunas usando CsvHelper

gistfile1.cs

using CsvHelper;
using CsvHelper.Configuration;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq.Expressions;
using Xunit;

namespace ClassLibrary1
{
    public class FluxoDeCaixa
    {
        public string Valor1 { get; set; }
        public string Valor2 { get; set; }
    }

    public class Teste
    {
        [Fact]
        public void TesteCsv()
        {
            var fluxos = new List<FluxoDeCaixa> { new FluxoDeCaixa { Valor1 = "1", Valor2 = "2" } };
            string csv;
            using (var stringWriter = new StringWriter())
            using (var csvWriter = new CsvWriter(stringWriter))
            {
                var propCsvConfigurator = new PropCsvConfigurator<FluxoDeCaixa>();
                propCsvConfigurator.MapeiaPropriedade("Valor1", "Valor10");
                propCsvConfigurator.MapeiaPropriedade("Valor2", "Valor20");
                csvWriter.Configuration.RegisterClassMap(propCsvConfigurator);

                csvWriter.WriteHeader<FluxoDeCaixa>();
                csvWriter.WriteRecords(fluxos);

                csv = stringWriter.ToString();
            }

            Assert.Equal(string.Format("Valor10,Valor20{0}1,2{0}", Environment.NewLine), csv);
        }
    }

    public class PropCsvConfigurator<T> : CsvClassMap<T>
    {
        public void MapeiaPropriedade(string propertyName, string newName)
        {
            var parameter = Expression.Parameter(typeof(T));
            var expression = Expression.Lambda<Func<T, object>>(Expression.Property(parameter, propertyName), parameter);
            Map(expression).Name(newName);
        }
    }
}