@Override
                public void onResponse(@NonNull final Call call, @NonNull final Response response) {
                    completed.set(true);
                    singleEmitter.onSuccess(response);
                }
Create a Single for running a cancellable request.

@param client  the client to use for this request
@param request the request
@return a Single containing the response or an IOException
main/src/main/java/cgeo/geocaching/utils/RxOkHttpUtils.java