how to reduce time to knit r markdown code example

Example: how to reduce time to knit r markdown

```{r dataProcess, cache = TRUE}
cars2 <- cars
save(cars2, "carsData.RData") # saves the 'cars2' dataset
```
and then we can just reload the data into the session:

```{r}
load("carsData.RData") # reloads the 'cars2' dataset
```