public function hasHeader($key, $toLower = true)
    {
        if ($toLower === true) {
            $key = strtolower($key);
        }
        return isset($this->_headers[$key]);
    }
public function hasHeader($key, $toLower = true)
    {
        if ($toLower === true) {
            $key = strtolower($key);
        }
        return isset($this->_headers[$key]);
    }
public function hasHeader ( $ key , $ toLower = true ) { if ( $ toLower === true ) { $ key = strtolower ( $ key ) ; } return isset ( $ this -> _headers [ $ key ] ) ; }
Check HTTP header is set or not
@param string $key the header key to be check, not case sensitive
@param boolean $toLower convert key to lowercase
@return boolean if there is http header with the name.
Check HTTP header is set or not