src/WorkerF/WorkerSocket/WorkerHttp.php
public static function getHeader($key)
    {
        if ( ! array_key_exists($key, HttpCache::$header)) {
            return NULL;
        }

        return HttpCache::$header[$key];
    }
public static function getHeader($key)
    {
        if ( ! array_key_exists($key, HttpCache::$header)) {
            return NULL;
        }

        return HttpCache::$header[$key];
    }
get http response header.

@param  string  $key
@return string