In the previous implementation an exception was thrown when the random
part reached 2^80. It meant that if the first random generated within a
millisecond was (2^80 - 1000), the generator could thrown the exception
when only 1000 requests was made. It was very difficult, but possible.
Now it only occurs in the extremely unlikely event that you manage to
generate more than 2^80 ULIDs within the same millisecond.
Fabio Lima