Test script for github.com/composer/composer/issues/4121

gistfile1.php

<?php

$url = '';

$headers = array(
    'User-Agent: DownloadTest',
    'Accept-Encoding: gzip',
    'Connection: close',
);

$options = array(
    'http' => array(
        'follow_location' => 1,
        'max_redirects' => 20,
        'protocol_version' => 1.1,
        'request_fulluri' => true,
        'header' => $headers,
    ),
);

if ('https' === parse_url($url, PHP_URL_SCHEME)) {
    $options['ssl']['SNI_enabled'] = true;
    if (PHP_VERSION_ID < 50600) {
        $options['ssl']['SNI_server_name'] = parse_url($url, PHP_URL_HOST);
    }
}

$options['http']['header'] = uasort($options['http']['header'], function ($k) {
    return preg_match('{^content-type}i', $k) ? 1 : -1;
});

$ctx = stream_context_create($options);

$result = file_get_contents($url, false, $ctx);