bievents.cs

var bi = new BulkInserter<Person>(sqlConnection, "People");
bi.PreBulkInsert += (sender, args) =>
    {
        // args.DataTable - this is the actual datatable being written to the server
        // you can modify the rows that will be written

        // args.Items - this is an array of the objects used to create the datatable
        // that will be written. modifying these objects at this point has no effect
        // on the bulk insert operation, but it's nice to have them if you need them
    };

bi.PostBulkInsert += (sender, args) => { /* same as PreBulkInsert, but after the insert happens */ };