docs: public static HttpResponse postJson(String urlStr, String body)
              throws IOException {
  
          URL url = new URL(urlStr);
          HttpURLConnection urlConnection = (HttpURLConnection) url
                  .openConnection();
          urlConnection.addRequestProperty("Accept", "application/json");
  
          urlConnection.setRequestMethod("POST");
  
          urlConnection.addRequestProperty("Content-Type", "application/json");
          urlConnection.addRequestProperty("Content-Length",
                  Integer.toString(body.length()));
          urlConnection.setDoOutput(true);
          urlConnection.setDoInput(true);
          urlConnection.setUseCaches(false);
  
          OutputStream out = urlConnection.getOutputStream();
          out.write(body.getBytes());
          ByteStreams.copy(new ByteArrayInputStream(body.getBytes()),
                  out);
          BufferedReader in = null;
          try {
              int errorCode = urlConnection.getResponseCode();
              if ((errorCode <= 202) && (errorCode >= 200)) {
                  in = new BufferedReader(new InputStreamReader(
                          urlConnection.getInputStream()));
              } else {
                  InputStream error = urlConnection.getErrorStream();
                  if (error != null) {
                      in = new BufferedReader(new InputStreamReader(error));
                  }
              }
  
              String json = null;
              if (in != null) {
                  json = CharStreams.toString(in);
              }
              return new HttpResponse(errorCode, json);
          } finally {
              if(in != null){
                  in.close();
              }
          }
      }