public static Response POST(Request request, Object url, Map<String, String> parameters, Map<String, File> files) {
List<Part> parts = new ArrayList<Part>();
for (String key : parameters.keySet()) {
final StringPart stringPart = new StringPart(key, parameters.get(key), request.encoding);
parts.add(stringPart);
}
for (String key : files.keySet()) {
Part filePart;