Estudo sobre stream_select

socket-server.php

<?php

$socket = stream_socket_server("tcp://0.0.0.0:8000", $errno, $errstr);

if (!$socket) {
    var_dump($errno, $errstr);
    exit(1);
}

while ($con = stream_socket_accept($socket)) {
    $timeout = rand(1, 5);
    sleep($timeout);

    fwrite($con, "Socket com espera de $timeout segundos");
    fclose($con);
}

fclose($socket);

stream_select.php

<?php

$streamList = [
    // Socket that takes rand(1, 5) seconds to respond
    stream_socket_client("tcp://0.0.0.0:8000", $errno, $errstr),
    fopen('teste.txt', 'r'),
];

foreach ($streamList as $stream) {
    stream_set_blocking($stream, false);
}

do {
    $streamCopy = $streamList;
    $select = stream_select($streamCopy, $write, $except, 0, 200000);
    if ($select === 0) continue;

    foreach ($streamCopy as $readStream) {
        unset($streamList[array_search($readStream, $streamList)]);
        echo stream_get_contents($readStream) . PHP_EOL;
    }
} while(!empty($streamList));