Really, really thanks for this

My final solution:

defmodule Speed2.BatchProcess do
  use GenServer
  @initial_state []
  @interval 10000

  def start_link do
    GenServer.start_link(__MODULE__, [])
  end

  def init(initial_data) do
    Process.send_after(self(), :tick, @interval)
    {:ok, initial_data}
  end

  def handle_info(:tick, state) do
    process(state)
    Process.send_after(self(), :tick, @interval)
    {:noreply, @initial_state}
  end

  def get_my_state(process_id) do
    GenServer.call(process_id, :get_the_state)
  end

  def push(process_id, value) do
    GenServer.call(process_id, {:push, value})
  end

  def clean(process_id) do
    GenServer.call(process_id, :clean)
  end

  def process(state) do
    IO.inspect state
  end

  def handle_call(:get_the_state, _from, my_state) do
    {:reply, my_state, my_state}
  end

  def handle_call({:push, value}, _from, my_state) do
    new_state = my_state ++ [value]
    case Enum.count(new_state) > 10 do
      true -> 
        process(new_state)
        {:reply, new_state, @initial_state}
      false ->
        {:reply, new_state, new_state}
    end
  end

  def handle_call(:clean, _from, my_state) do
    {:reply, my_state, @initial_state}
  end
end