Process::nextStage

public function nextStage()
{
	$this->stage++;
	$this->step = 0;

	if ($this->stage < count($this->stages))
	{
		$stageCode = $this->stages[$this->stage]['CODE'] ?? 'UNDEFINED for '.$this->stage;
	}
	else
	{
		$stageCode = 'FINAL';
	}

	$this->logMessage(
		'### NEXT STAGE >>> ' . $stageCode
		. ' in ' . $this->getElapsedTimeString()
		. ', mem peak = ' . $this->getMemoryPeakString() . ' mb'
	);
}