Hi,

I have just sent a PR, adding a `return_counts` keyword argument to `np.unique` that does exactly what the name suggests: counting the number of times each unique time comes up in the array. It reuses the `flag` array that is constructed whenever any optional index is requested, extracts the indices of the `True`s in it, and returns their diff. You can check it here:

https://github.com/numpy/numpy/pull/4180

Regards,

Jaime