function onIterations( error, iter ) {
		// If provided an error, then a benchmark failed, and, similar to pretests, don't run the benchmark multiple times...
		if ( error ) {
			opts.repeats = 1;
			opts.iterations = 1;
			return clbk( name, opts, benchmark );
		}
		opts.iterations = iter;
		return clbk( name, opts, benchmark );
	}
Callback invoked upon determining an iteration number.

@private
@param {(Error|null)} error - error object
@param {PositiveInteger} iter - number of iterations
@returns {void}