Function type declaration for UCharIterator.setState().
Restore the "state" of the iterator using a state word from a getState() call. The iterator object need not be the same one as for which getState() was called, but it must be of the same type (set up using the same uiter_setXYZ function) and it must iterate over the same string (binary identical regardless of memory address). For more about the state word see UCharIteratorGetState.
After calling setState(), a getIndex(UITER_CURRENT) may be slow because the UTF-16 index may not be restored as well, but the iterator can deliver the correct text contents and move relative to the current position without performance degradation.