# File lib/system_timer/concurrent_timer_pool.rb, line 45
45:     def next_expired_timer(now_in_seconds_since_epoch)
46:       candidate_timer = next_timer
47:       return nil if candidate_timer.nil? || 
48:                     candidate_timer.trigger_time > now_in_seconds_since_epoch
49:       candidate_timer
50:     end