Returns the SequenceIter which is delta positions away from
this.
If this is closer than -delta positions to the beginning of the sequence, the begin
iterator is returned. If this is closer than delta positions to the end of the sequence,
the end iterator is returned.
| this | |
| delta |
A positive or negative number indicating how many positions away from this the returned SequenceIter will be |
|
a SequenceIter which is |