module ActiveSupport::ForkTracker

def after_fork(&block)
  @callbacks << block
  block
end

def after_fork_callback
  new_pid = Process.pid
  if @pid != new_pid
    @callbacks.each(&:call)
    @pid = new_pid
  end
end

def hook!
  ::Process.singleton_class.prepend(CoreExt)
end

def unregister(callback)
  @callbacks.delete(callback)
end