BufferArea::begin

public function begin($stub = null)
{
	if ($this->started)
	{
		throw new NotSupportedException("begin() has been called. Frame id: ".$this->getId().".");
	}

	$this->startDynamicArea();

	$this->started = true;
	$this->staticPart = $stub;
	ob_start();
	return $this;
}