/**
  * Always add a x-amz-content-sha-256 for data integrity.
  */
 public function presign(RequestInterface $request, CredentialsInterface $credentials, $expires)
 {
     if (!$request->hasHeader('x-amz-content-sha256')) {
         $request = $request->withHeader('X-Amz-Content-Sha256', $this->getPresignedPayload($request));
     }
     return parent::presign($request, $credentials, $expires);
 }
 private function createPresignedUrl(AwsClientInterface $client, CommandInterface $cmd)
 {
     $newCmd = $client->getCommand('CopySnapshot', $cmd->toArray());
     // Avoid infinite recursion by flagging the new command.
     $newCmd->__skipCopySnapshot = true;
     // Serialize a request for the CopySnapshot operation.
     $request = \ILAB_Aws\serialize($newCmd);
     // Create the new endpoint for the target endpoint.
     $endpoint = EndpointProvider::resolve($this->endpointProvider, ['region' => $cmd['SourceRegion'], 'service' => 'ec2'])['endpoint'];
     // Set the request to hit the target endpoint.
     $uri = $request->getUri()->withHost((new Uri($endpoint))->getHost());
     $request = $request->withUri($uri);
     // Create a presigned URL for our generated request.
     $signer = new SignatureV4('ec2', $cmd['SourceRegion']);
     return (string) $signer->presign(SignatureV4::convertPostToGet($request), $client->getCredentials()->wait(), '+1 hour')->getUri();
 }