QST:how can i cut down time when using pandas.style.to_excel()?
#### Question about pandas
  I tested the function  **to_excel()**  from the following code using xlsx file which size is **50**M. 
the result is **df_style_red_mark**  spend 350s ,but **df** spend 60s. And i want to know why it is?
how can i cut down time when using **df_style_red_mark**?
```python
df_style_red_mark = df.style.apply(...)
```

```python
df_style_red_mark.to_excel(...)

df.to_excel(...)
```
