What is the best way to get the list of column names using CsvHelper?

The previous answer used to work fine, but as of version 20 of csvhelper there is a breaking change. Now just access the header record from the reader directly:

csv.Read();
csv.ReadHeader();
string[] headerRow = csv.HeaderRecord;

The header record is on the csv context. It needs to be read beforehand before accessing.

csv.Read();
csv.ReadHeader();
string[] headerRow = csv.Context.HeaderRecord;