class DEBUGGER__::Session

def get_thread_client th = Thread.current

can be called by other threads
def get_thread_client th = Thread.current
  if @th_clients.has_key? th
    @th_clients[th]
  else
    if Thread.current == @session_server
      create_thread_client th
    else
      ask_thread_client th
    end
  end
end