public function setContent($records, callable $callback = null)
	{
		$this->content = $records;
		$this->callback = $callback;
		return $this;
	}
public function setContent($records, callable $callback = null)
	{
		$this->content = $records;
		$this->callback = $callback;
		return $this;
	}
public function setContent ( $ records , callable $ callback = null ) { $ this -> content = $ records ; $ this -> callback = $ callback ; return $ this ; }
Set the content records along with an optional callback to render them into CSV fields

@param array|\Traversable $records
@param callable $callback

@return CsvExport
Set the content records along with an optional callback to render them into CSV fields