docs: public static int getPid(Process process) {
          if (!process.getClass().getName().equals("java.lang.UNIXProcess"))
              throw new UnsupportedOperationException("This operation is only supported in POSIX environments (Linux/Unix/MacOS");
          if (pidField == null) { // benign race
              try {
                  Field f = process.getClass().getDeclaredField("pid");
                  f.setAccessible(true);
                  pidField = f;
              } catch (NoSuchFieldException e) {
                  throw new AssertionError(e);
              } catch (SecurityException e) {
                  throw new RuntimeException(e);
              }
          }
  
          try {
              return pidField.getInt(process);
          } catch (IllegalAccessException e) {
              throw new AssertionError(e);
          }
      }