Progression instance that behaves like a range of integers, from 0 to the given
ending value, exclusive.Progression instance that behaves like a range of all valid indices
of the given array.Progression instance with the given starting, ending, and stepping
values.Progressions API.Progression outside of this library.Progression instance that behaves like a range of integers, with the given
starting and ending values.Progression instance whose starting value is this progression's ending value,
and whose ending value is this progression's starting value.Integer array filled with all the integers in this progression, in iteration order.