src/Whip.php
private function normalizeHeaderName($header)
    {
        if (strpos($header, 'HTTP_') === 0) {
            $header = str_replace('_', '-', substr($header, 5));
        }
        return strtolower($header);
    }
private function normalizeHeaderName($header)
    {
        if (strpos($header, 'HTTP_') === 0) {
            $header = str_replace('_', '-', substr($header, 5));
        }
        return strtolower($header);
    }
private function normalizeHeaderName ( $ header ) { if ( strpos ( $ header , 'HTTP_' ) === 0 ) { $ header = str_replace ( '_' , '-' , substr ( $ header , 5 ) ) ; } return strtolower ( $ header ) ; }
Normalizes HTTP header name representations.

HTTP_MY_HEADER and My-Header would be transformed to my-header.

@param string $header The original header name.
@return string The normalized header name.
Normalizes HTTP header name representations .