moveNext abstract method
Moves the range to be the next count
characters after the current range.
The new range starts and the end of the current range and includes
the next count
characters, or as many as available if there
are fewer than count
characters following the current range.
The count
must not be negative.
If it is zero, the call has the same effect as collapseToEnd.
Returns true
if there were count
following characters
and false
if not.
Implementation
@override
bool moveNext([int count = 1]);