<?php
$key = '9VLNIsCS+BzH6wbu1ZvBlHVQbJq5lGw0';
$fp = stream_socket_client('tcp://localhost:30033', $errno, $errstr, 30, STREAM_CLIENT_CONNECT);
if (!$fp) {
    die('connection failed');
}

fwrite($fp, $key);
$data = file_get_contents('test.png');

$size = strlen($data);
$seek = 0;
$pack = 4096;

for (; $seek < $size;) {
    $rest = $size-$seek;
    $pack = $rest < $pack ? $rest : $pack;
    $buff = substr($data, $seek, $pack);
    $seek = $seek+$pack;

    fwrite($fp, $buff);
}

fclose($fp);