一小段代码理解Fiber

server = Fiber.new do |request|  puts 'Server Started'  while(request != 'exit')    puts "Received request: #{request}"    request = Fiber.yield Random.rand  endendresponse = server.resume 'hi'puts responseresponse = server.resume 'hello'puts responseresponse = server.resume 'exit'puts responseserver.resume '???'