Curl::stream_headers( resource|CurlHandle $handle, string $headers ): integer

506	public function stream_headers($handle, $headers) {507		// Why do we do this? cURL will send both the final response and any508		// interim responses, such as a 100 Continue. We don't need that.509		// (We may want to keep this somewhere just in case)510		if ($this->done_headers) {511			$this->headers      = '';512			$this->done_headers = false;513		}514 515		$this->headers .= $headers;516 517		if ($headers === "\r\n") {518			$this->done_headers = true;519		}520 521		return strlen($headers);522	}