repro.rb

require 'celluloid/io'
require 'socket'

class Server
  include Celluloid::IO

  def run
    @tcp = TCPServer.new('0.0.0.0', 31337)
    loop do
      Connection.new_link(@tcp.accept).async.run
    end
  end

  class Connection
    include Celluloid

    finalizer :shutdown

    def initialize(socket)
      @socket = socket
    end

    def run
      while !@socket.closed? do
        @socket.write(@socket.readpartial(4096))
      end
    rescue EOFError, Errno::ECONNRESET

    end

    def shutdown
      puts "Shutdown called"
      @socket.close
    end
  end
end

class Client
  def initialize(host, port)
    @tcp = TCPSocket.new(host, port)
  end

  def write(data)
    @tcp.write(data)
  end

  def shutdown
    @tcp.close
  end
end

s = Server.new
s.async.run
c = Client.new('localhost', 31337)
sleep 1
s.terminate

# Could not cleanly terminate