docs: protected Bundle unmarshalFeed(HttpResponse response, String format) {
      Bundle feed = null;
      byte[] cnt = log(response);
      String contentType = response.getHeaders("Content-Type")[0].getValue();
      OperationOutcome error = null;
      try {
        if (cnt != null) {
          if(contentType.contains(ResourceFormat.RESOURCE_XML.getHeader()) || contentType.contains("text/xml+fhir")) {
            Resource rf = getParser(format).parse(cnt);
            if (rf instanceof Bundle)
              feed = (Bundle) rf;
            else if (rf instanceof OperationOutcome && hasError((OperationOutcome) rf)) {
              error = (OperationOutcome) rf;
            } else {
              throw new EFhirClientException("Error reading server response: a resource was returned instead");
            }
          }
        }
      } catch(IOException ioe) {
        throw new EFhirClientException("Error reading Http Response", ioe);
      } catch(Exception e) {
        throw new EFhirClientException("Error parsing response message", e);
      }
      if(error != null) {
        throw new EFhirClientException("Error from server: "+ResourceUtilities.getErrorDescription(error), error);
      }
      return feed;
    }