it perf test

it.php

<?php

namespace Soyuka\Marsh\Tests;

$a = [];

for ($i=0; $i < 10000; $i++) { 
    $o = new \stdClass();
    $o->i = $i;
    $a[] = $o;
}

$output = new class () {
    public function write() {}
};

$time_start = microtime(true);

$it = new \ArrayIterator($a);
$valid = $it->valid();
while ($valid) {
    $output->write("\"{$it->key()}\":");
    $output->write(json_encode($it->current()));
    $it->next();
    $valid = $it->valid();
    if ($valid) {
        $output->write(',');
    }
}

$time_end = microtime(true);
$time = $time_end - $time_start;

echo "Array iterator took $time seconds\n";

$time_start = microtime(true);

$start = "";
foreach ($a as $key => $value) {
    $output->write("$start\"{$key}\":");
    $output->write(json_encode($value));
    $start = ",";
}

$time_end = microtime(true);
$time = $time_end - $time_start;

echo "Foreach took $time seconds\n";