csv_writer_free doesn't set pointers to NULL after free

[Kwanddwo]

csv_writer_free has a different behaviour compared to csv_reader_free:

csv_writer_free:

void csv_writer_free(CSVWriter *writer) {
    if (!writer) return;
    
    if (writer->file && writer->owns_file) {
        fflush(writer->file);
        fclose(writer->file);
    }
    
    if (writer->config && writer->owns_config) {
        csv_config_free(writer->config);
    }
    

} 

csv_reader_free:

void csv_reader_free(CSVReader *reader) {
    if (reader) {
        if (reader->file) {
            fclose(reader->file);
            reader->file = NULL;
        }

        if (reader->owns_arenas) {
            if (reader->persistent_arena) {
                arena_destroy(reader->persistent_arena);
                free(reader->persistent_arena);
                reader->persistent_arena = NULL;
            }
            if (reader->temp_arena) {
                arena_destroy(reader->temp_arena);
                free(reader->temp_arena);
                reader->temp_arena = NULL;
            }
            free(reader);
        } else {
            reader->persistent_arena = NULL;
            reader->temp_arena = NULL;
        }
    }
}

csv_writer_free doesn't set freed pointers to NULL