Empty file checking

[sabari-shankar]

I'm using ToModel Concerns to upload the file data into DB
I need to validate if the file has empty please give some Idea to validate it

class BulkImport implements ToModel,WithHeadingRow,WithBatchInserts,WithValidation
{
        public function model(array  $rows)
    {
            User::create($rows)
    }
}