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 check!
  # We trust the `_fork` callback
end

def hook!
  if Process.respond_to?(:_fork) # Ruby 3.1+
    ::Process.singleton_class.prepend(ModernCoreExt)
  elsif Process.respond_to?(:fork)
    ::Object.prepend(CoreExtPrivate) if RUBY_VERSION < "3.0"
    ::Kernel.prepend(CoreExtPrivate)
    ::Kernel.singleton_class.prepend(CoreExt)
    ::Process.singleton_class.prepend(CoreExt)
  end
end

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