@kha I have added `timeit` for running experiments for the paper.
We have to be careful because `timeit` may produce incorrect results
due to compiler optimizations (e.g., ground term extraction).
Here are examples that do not produce the result we expect:
```
def main : io uint32 :=
timeit "tst" (io.println' ("result " ++ to_string (tst 1000000))) *>
pure 0
```
```
def main (xs : list string) : io uint32 :=
timeit "tst" (io.println' ("result " ++ to_string (tst xs.head.to_nat))) *>
pure 0
```
