private static int validatePid(@Nullable Object value) {
            if (!(value instanceof Number)) {
                return -1;
            } else {
                 final int pid = ((Number) value).intValue();
                 return pid > 0 ? pid : -1;
            }
        }
Returns {@code true} if the operating system is Linux.
core/src/main/java/com/linecorp/armeria/common/util/SystemInfo.java