src/Twitter/Connections/Connection.php
private function setGuzzleHeaders(RequestInterface $request, array $headers)
    {
        //iterate over the headers array and set each item
        foreach ($headers as $key => $value) {
            //Sets Header
            $request->setHeader($key, $value);
        }

        //return the request
        return $request;
    }
private function setGuzzleHeaders(RequestInterface $request, array $headers)
    {
        //iterate over the headers array and set each item
        foreach ($headers as $key => $value) {
            //Sets Header
            $request->setHeader($key, $value);
        }

        //return the request
        return $request;
    }
Set Headers for a Request specified by $headers.

@param RequestInterface $request a Guzzle Request
@param array            $headers headers to set (should be an assoc array).