为什么并发红宝石立即退出

Question

我尝试使用concurrent-ruby来完成一些并行任务，我遵循文档并使用Concurrent::Async：

require 'concurrent'

class Echo
  include Concurrent::Async

  def echo(msg)
    p msg
  end
end

horn = Echo.new
horn.async.echo('one')

并在终端中运行它，但是过程什么也没打印，然后立即退出

Answer 1

require 'concurrent'

class Echo
  include Concurrent::Async

  def echo(msg)
    p msg
  end
end

horn = Echo.new

# t is an instance of Concurrent::IVar which includes Concurrent::Concern::Obligation
t = horn.async.echo('one')

# wait until obligation is complete or the timeout has been reached
t.wait! 

souce code