public function rewind()
	{
		$this->file->rewind();
		if ($this->useFirstRecordAsHeader)
		{
			if (!$this->file->valid())
			{
				throw new \RuntimeException('Expected first row to be header, but reached EOF instead');
			}
			$this->header = $this->file->current();
			$this->file->next();
		}
	}