toArray() improvement

[issei-m]

This PR changes toArray() logic using built-in iterator_to_array function. Bringing a little performance improvement without changing behavior against previous version.

This time, I simply tested with following snippet:

<?php require __DIR__ . '/vendor/autoload.php';

define('ITEMS_COUNT', 100000);
define('TRY_COUNT', 100);

$grandchildren = array_fill(0, ITEMS_COUNT, 'grand child');
$grandchildren[] = array_fill(0, ITEMS_COUNT, 'great grandchild');

// with Array

$array = array_fill(0, ITEMS_COUNT, 'x');
$array[] = $grandchildren;
$coll = \DusanKasan\Knapsack\Collection::from($array);

$st = microtime(true);
for ($i = 0; $i < TRY_COUNT; $i++) $coll->toArray();
printf("with array -> AVG: %.6f [s]\n", (microtime(true) - $st) / TRY_COUNT);

// with Generator

$generator = function () use ($grandchildren) {
    for ($i = 0; $i < ITEMS_COUNT; $i++) {
        yield 'x';
    }
    yield $grandchildren;
};
$coll = \DusanKasan\Knapsack\Collection::from($generator);

$st = microtime(true);
for ($i = 0; $i < TRY_COUNT; $i++) $coll->toArray();
printf("with Generator -> AVG: %.6f [s]\n", (microtime(true) - $st) / TRY_COUNT);

// show memory usage

printf("Peak Memory Usage : %.3f [MB]\n", memory_get_peak_usage() / (1024 * 1024));

before

with array -> AVG: 0.022309 [s]
with Generator -> AVG: 0.202728 [s]
Peak Memory Usage : 21.252 [MB]

after

with array -> AVG: 0.008613 [s]
with Generator -> AVG: 0.174608 [s]
Peak Memory Usage : 21.252 [MB]

For generator is not very improved but for array is 2x+ faster.

[DusanKasan]

Thank you for the contribution!