function createBenchmark( len, dtype ) {
	var arr;
	var i;

	arr = [];
	for ( i = 0; i < len; i++ ) {
		arr.push( i );
	}
	return benchmark;

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

		b.tic();
		for ( i = 0; i < b.iterations; i++ ) {
			out = convertArray( arr, dtype );
			if ( out.length !== len ) {
				b.fail( 'unexpected length' );
			}
		}
		b.toc();
		if ( !isCollection( out ) ) {
			b.fail( 'should return an array-like object' );
		}
		b.pass( 'benchmark finished' );
		b.end();
	}
}
Creates a benchmark function.

@private
@param {PositiveInteger} len - array length
@param {string} dtype - data type
@returns {Function} benchmark function