How do I free memory?

[yunhyejoung]

How do I free memory?

using Sylvan.Data;
using Sylvan.Data.Csv;
using System.Linq;

using var dr = CsvDataReader.Create("data.csv");
IEnumerable records = dr.GetRecords();

IDataReader dr = records.AsDataReader().AsDbDataReader();

while( dr.Read() ) //<===== have to do dr.Read()
{
.............
}