How to check if record exists before reading in Dapper ORM

Can anyone please suggest how to check if there are any records in the resultset using Dapper ORM.

Customer objCustomer = null;
using (SqlMapper.GridReader multiResult = new DapperRepository().QueryMultiple(sql, new { id = id }))
{
    objCustomer = multiResult.Read<Customer>().Single(); //null exception
}