CsvHelperToSqlBulkData.cs

using (var sqlBulkCopy = new SqlBulkCopy(connectionString, SqlBulkCopyOptions.Default))
{
    const int timeout = 1200;

    sqlBulkCopy.BulkCopyTimeout = timeout;
    sqlBulkCopy.BatchSize = 50000;
    sqlBulkCopy.DestinationTableName = "dbo.MyTable";
    sqlBulkCopy.NotifyAfter = 1000000;
    sqlBulkCopy.SqlRowsCopied += SqlBulkCopy_SqlRowsCopied;

    foreach (var sqlBulkCopyColumnMapping in columnMappings)
    {
        sqlBulkCopy.ColumnMappings.Add(sqlBulkCopyColumnMapping);
    }

    using (var csvReader = new CsvReader(File.OpenText(tempFile)))
    {
        using (var csvDataReader = new CsvDataReader(csvReader))
        {
            sqlBulkCopy.WriteToServer(csvDataReader);
        }
    }
}