Phly\Http\Response\SapiEmitter::emit PHP Method

    public function emit(ResponseInterface $response, $maxBufferLevel = null)
    {
        if (headers_sent()) {
            throw new RuntimeException('Unable to emit response; headers already sent');
        }
        $this->emitStatusLine($response);
        $this->emitHeaders($response);
        $this->emitBody($response, $maxBufferLevel);
    }