src/HeaderTrait.php
public function addHeader($name)
    {

        // add the header
        $this->headers[$name] = $position = sizeof($this->headers);

        // return the new header's position
        return $position;
    }
public function addHeader($name)
    {

        // add the header
        $this->headers[$name] = $position = sizeof($this->headers);

        // return the new header's position
        return $position;
    }
Add's the header with the passed name and position, if not NULL.

@param string $name The header name to add

@return integer The new headers position