class DEBUGGER__::UI_TcpServer

def initialize host: nil, port: nil
  @local_addr = nil
  @host = host || CONFIG[:host]
  @port_save_file = nil
  @port = begin
    port_str = (port && port.to_s) || CONFIG[:port] || raise("Specify listening port by RUBY_DEBUG_PORT environment variable.")
    case port_str
    when /\A\d+\z/
      port_str.to_i
    when /\A(\d+):(.+)\z/
      @port_save_file = $2
      $1.to_i
    else
      raise "Specify digits for port number"
    end
  end
  @uuid = nil # for CDP
  super()
end