protected static ScheduledExecutorService getExpiryExecutor() {
    return expiryExecutor;
  }
Schedules the entry to expire based on the following: the expiration time sent may either be
Unix time (number of seconds since January 1, 1970, as a 32-bit value), or a number of seconds
starting from current time. In the latter case, this number of seconds may not exceed
60*60*24*30 (number of seconds in 30 days); if the number sent by a client is larger than that,
the server will consider it to be real Unix time value rather than an offset from current time.
geode-memcached/src/main/java/org/apache/geode/internal/memcached/commands/StorageCommand.java