Concatenate streams without bloating the memory.
$ composer install keven/append-stream<?php
use Keven\AppendStream\AppendStream;
// Concatenate 3 streams
$handle = (new AppendStream([
fopen('data:https://text/plain,stream1','r'),
fopen('data:https://text/plain,stream2','r'),
fopen('data:https://text/plain,stream3','r'),
]))->getResource();
echo stream_get_contents($handle);
// stream1stream2stream3