okhttp-decode-gzip-response

    private String decodeBody(Response response) throws IOException {
        final ResponseBody body = response.body();
        if (body == null) return null;

        if (isZipped(response)) {
            return unzip(response.body());
        } else {
            return body.string();
        }
    }

    private boolean isZipped(Response response) {
        return "gzip".equalsIgnoreCase(response.header("Content-Encoding"));
    }

    private String unzip(ResponseBody body) {
        try {
            GzipSource responseBody = new GzipSource(body.source());
            return Okio.buffer(responseBody).readUtf8();
        } catch (IOException e) {
            return null;
        }
    }