public function getHeader(string $name): string {
        $lines = $this->getHeaderLines($name);
        return implode(',', $lines);
    }
public function getHeader(string $name): string {
        $lines = $this->getHeaderLines($name);
        return implode(',', $lines);
    }
public function getHeader ( string $ name ) : string { $ lines = $ this -> getHeaderLines ( $ name ) ; return implode ( ',' , $ lines ) ; }
Retrieves a header by the given case-insensitive name, as a string.

This method returns all of the header values of the given
case-insensitive header name as a string concatenated together using
a comma.

NOTE: Not all header values may be appropriately represented using
comma concatenation. For such headers, use getHeaderLines() instead
and supply your own delimiter when concatenating.

@param string $name Case-insensitive header field name.
@return string
Retrieves a header by the given case - insensitive name as a string .