<?php

class Buffer {

    private $buffer = '';

    private $puffs = 0;

    public function start() {
        ob_start($this->getCallback());
    }

    private function buff(string $string) {
        $this->buffer .= $string;
        echo ".";
    }

    public function stop() {
        ob_end_clean();
    }

    public function report(): string {
        return $this->buffer;
    }

    private function getCallback(): callable  {
        return function(string $str) {
            $this->buff($str);
        };
    }

    public function puff() {
        $this->stop();
        if ($this->puffs > 3) {
            $this->puffs = 0;
            echo "\r";
        }
        echo '.';
        $this->puffs++;
        $this->start();
    }
}

$buffer = new Buffer();

$buffer->start();

foreach (range(0, 10) as $id) {
    echo "Hello world {$id}", PHP_EOL;
    $buffer->puff();
    usleep(500000);
}

$buffer->stop();

echo PHP_EOL,"Buffering ended", PHP_EOL;

echo $buffer->report();