Return the number of loops and time taken so that
total time >= target_time (default is 0.2 seconds).
Calls the timeit method with increasing numbers from the sequence
1, 2, 5, 10, 20, 50, ... until the target time is reached.
Returns (number, time_taken).
If *callback* is given and is not None, it will be called after
each trial with two arguments: ``callback(number, time_taken)``.