IExcelReader Interface

var reader = Readers.GetExcelReader();
using(reader.Open(documentApi.OpenRead(ctx.Input.DocumentAttribute)))
{
    var workSheetReader = reader.GetSheet(0);
    var rowCount = workSheetReader.RowCount;
    var columnCount = workSheetReader.ColumnCount;
    for (int row = 0; row < rowCount; row++) {
        for (int col = 0; col < columnCount; col++) {
            var value = workSheetReader.Read<string>(row, col);
        }
    }
}