oob output handling

<?php

class oob {
	private $buffer = '';
	private $oob = '';
	function __construct() {
		ob_start([$this, 'obhandler']);
	}

	function __destruct() {
		ob_end_flush();
		echo $this->buffer;
	}

	function oob($buffer) {
		$this->oob .= $buffer;
		ob_flush();
	}

	function obhandler($buffer){
		$this->buffer .= $buffer;
		$oob = $this->oob;
		$this->oob = '';
		return $oob;
	}
}


$oob = new oob();
for($i=0 ; $i<10 ; $i++) {
	print "frop".$i."\n";
	$oob->oob('frml'.$i."\n");
}
unset($oob);

de output is:
frml0
frml1
frml2
frml3
frml4
frml5
frml6
frml7
frml8
frml9
frop0
frop1
frop2
frop3
frop4
frop5
frop6
frop7
frop8
frop9