function createBenchmark( len ) {
	return benchmark;

	/**
	* Benchmark function.
	*
	* @private
	* @param {Benchmark} b - benchmark instance
	*/
	function benchmark( b ) {
		var iter;
		var v;
		var i;
		var j;

		b.tic();
		for ( i = 0; i < b.iterations; i++ ) {
			iter = iterCompositesSeq();
			for ( j = 0; j < len; j++ ) {
				v = iter.next().value;
				if ( v !== v ) {
					b.fail( 'should not return NaN' );
				}
			}
		}
		b.toc();

		v = iter.next().value;
		if ( v !== v ) {
			b.fail( 'should not return NaN' );
		}
		b.pass( 'benchmark finished' );
		b.end();
	}
}
Creates a benchmark function.

@private
@param {PositiveInteger} len - number of iterations
@returns {Function} benchmark function