docs: private static long getRSSFromProcFS() {
          try {
              File statFile = new File(String.format("/proc/%d/stat", pid));
              FileInputStream fis = new FileInputStream(statFile);
              try {
                  BufferedReader r = new BufferedReader(new InputStreamReader(fis));
                  String stats = r.readLine();
                  String[] parts = stats.split(" ");
                  return Long.parseLong(parts[23]) * 4 * 1024;
              } finally {
                  fis.close();
              }
          }
          catch (Exception e) {
              return -1;
          }
      }