ext-uv/examples/udp_bind.php

<?php
$udp = uv_udp_init();
var_dump($udp);

uv_udp_bind($udp, uv_ip4_addr('0.0.0.0',10000));

uv_udp_recv_start($udp,function($buffer,$udp){
    echo "recv:" .  $buffer;
    
    uv_close($udp);
});

$uv = uv_udp_init();
uv_udp_send($uv, "Hello", uv_ip4_addr("0.0.0.0",10000),function($s,$uv){
    echo "success" . PHP_EOL;
    uv_close($uv);
});

uv_run();