{{alias}}( iterator, fcn[, offset[, eager]][, thisArg] )
    Returns an iterator which steps according to a provided callback function.

    When invoked, the input function is provided four arguments:

    - value: iterated value.
    - i: input iteration index (zero-based).
    - n: output (strided) iteration index (zero-based).
    - curr: current stride.

    The return value of the input function specifies the next stride.

    If an environment supports Symbol.iterator and a provided iterator is
    iterable, the returned iterator is iterable.

    Parameters
    ----------
    iterator: Object
        Input iterator.

    fcn: Function
        Stride function (i.e., a function which returns the step amount).

    offset: integer (optional)
        Index of the first iterated value. Default: 0.

    eager: boolean (optional)
        Boolean indicating whether to eagerly advance the input iterator when
        provided a non-zero offset. Default: false.

    thisArg: any (optional)
        Stride function execution context.

    Returns
    -------
    iterator: Object
        Iterator.

    iterator.next(): Function
        Returns an iterator protocol-compliant object containing the next
        iterated value (if one exists) and a boolean flag indicating whether the
        iterator is finished.

    iterator.return( [value] ): Function
        Finishes an iterator and returns a provided value.

    Examples
    --------
    > var arr = {{alias:@stdlib/array/to-iterator}}( [ 0, 1, 2, 3, 4, 5, 6 ] );
    > function stride( v, i ) { return (i % 10)+1; };
    > var it = {{alias}}( arr, stride );
    > var r = it.next().value
    0
    > r = it.next().value
    1
    > r = it.next().value
    3

    See Also
    --------