class EventMachine::Completion

def stateback(state, *a, &b)
  # The following is quite unfortunate special casing for :completed
  # statebacks, but it's a necessary evil for latent completion
  # definitions.
  if :completed == state || !completed? || @state == state
    @callbacks[state] << EM::Callback(*a, &b)
  end
  execute_callbacks
  self
end