class DEBUGGER__::UI_ServerBase

def readline prompt
  input = (sock(skip: CONFIG[:skip_bp]) do |s|
    next unless s
    if @repl
      raise "not in subsession, but received: #{line.inspect}" unless @session.in_subsession?
      line = "input #{Process.pid}"
      DEBUGGER__.debug{ "send: #{line}" }
      s.puts line
    end
    sleep 0.01 until @q_msg
    @q_msg.pop.tap{|msg|
      DEBUGGER__.debug{ "readline: #{msg.inspect}" }
    }
  end || 'continue')
  if input.is_a?(String)
    input.strip
  else
    input
  end
end