Very low memory usage iterator

index.php

<?php

function m()
{
    $memory = round(memory_get_usage() / 1024 / 1024, 2);
    $frame = debug_backtrace(0, 1)[0];
    $file = basename($frame['file']);
    $line = $frame['line'];

    printf("%s:%d | %sMb\n", $file, $line, $memory);
}

function gen(): \iterator
{
    $data = str_repeat('x', 10 * 1024 * 1024);
    $i = 0;

    while ($data) {
        m();
        yield $data;
        m();
        unset($data);
        yield;
        m();
        ++$i;
        // Simulate the API return nothing
        if ($i == 3) {
            $data = false;
        } else {
            $data = str_repeat('x', 10 * 1024 * 1024);
        }
        m();
    }
};

m();

foreach ($gen = gen() as $k => $v) {
    $gen->next();
    m();
    unset($k, $v);
    m();
}

m();

result.txt

JHS6W:36 | 0.37Mb
JHS6W:19 | 10.38Mb
JHS6W:21 | 10.38Mb
JHS6W:40 | 10.38Mb
JHS6W:42 | 0.37Mb
JHS6W:24 | 0.37Mb
JHS6W:32 | 10.38Mb
JHS6W:19 | 10.38Mb
JHS6W:21 | 10.38Mb
JHS6W:40 | 10.38Mb
JHS6W:42 | 0.37Mb
JHS6W:24 | 0.37Mb
JHS6W:32 | 10.38Mb
JHS6W:19 | 10.38Mb
JHS6W:21 | 10.38Mb
JHS6W:40 | 10.38Mb
JHS6W:42 | 0.37Mb
JHS6W:24 | 0.37Mb
JHS6W:32 | 0.37Mb
JHS6W:45 | 0.37Mb

https://3v4l.org/JHS6W