我有以下内容：
/config/delayed_job_config.rb
# Enable DelayedJob Logging
Delayed::Worker.logger = Rails.logger
Delayed::Worker.logger.auto_flushing = 1
# Do not delete failed jobs (default is true)
Delayed::Worker.destroy_failed_jobs = false
# Dont wait so long between jobs
Delayed::Worker.read_ahead = 100 # default was 5
Delayed::Worker.sleep_delay = 1 #default was 5
这里的问题是没有使用设置：
$ rails c
Loading development environment (Rails 3.2.5)
1.9.3-p125 :001 > Delayed::Worker.read_ahead
=> 5
1.9.3-p125 :002 > Delayed::Worker.sleep_delay
=> 5
任何想法在这里有什么问题？感谢