src/HttpClient/Plugin/SignaturePlugin.php
public function handleRequest(RequestInterface $request, callable $next, callable $first)
    {
        $encryptedBody = $this->encrypter->encrypt($request->getBody()->getContents());
        $signature = sprintf('%s %s %s', $this->apiKey, 'RS256-hex', $encryptedBody);

        return $next(
            $request->withHeader('Signature', $signature)
        );
    }
public function handleRequest(RequestInterface $request, callable $next, callable $first)
    {
        $encryptedBody = $this->encrypter->encrypt($request->getBody()->getContents());
        $signature = sprintf('%s %s %s', $this->apiKey, 'RS256-hex', $encryptedBody);

        return $next(
            $request->withHeader('Signature', $signature)
        );
    }
{@inheritdoc}