Errors

=ERROR REPORT==== 11-Aug-2016::10:21:41 ===
** Generic server schedule_ingestor terminating 
** Last message in was fetch_schedule_data
** When Server state == #{timer => #Ref<0.0.4.267>}
** Reason for termination == 
** {{case_clause,{nil,100,0,nil}},
    [{'Elixir.Stream',do_resource,5,[{file,"lib/stream.ex"},{line,1099}]},
     {'Elixir.Stream',run,1,[{file,"lib/stream.ex"},{line,494}]},
     {'Elixir.MyGenServer',
         handle_info,2,
         [{file,
              "lib/gen_server_test/my_gen_server.ex"},
          {line,23}]},
     {gen_server,try_dispatch,4,[{file,"gen_server.erl"},{line,615}]},
     {gen_server,handle_msg,5,[{file,"gen_server.erl"},{line,681}]},
     {proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,240}]}]}

Failing genserver

defmodule MyGenServer do
  use GenServer
  
  def start_link(name) do
    GenServer.start_link(__MODULE__, [], name: name)
  end
  
  def init(state) do
    IO.puts "INIT"
    :hackney.start
    timer = Process.send_after(self(), :fetch_schedule_data, 1000)
    { :ok, %{ timer: timer } }
  end
  
  def handle_info(:fetch_schedule_data, %{ timer: timer } = state) do
    IO.puts "Fetch data started"
    Stream.resource(fn -> begin_download end,
                    &continue_download/1,
                    &finish_download/1)
    |> Stream.run

    { :noreply, state }
  end
  
  defp begin_download do
    IO.puts "Starting download"
    { nil, 100, 0, nil }
  end
  
  defp continue_download({ client, total_size, size, file } = p) do
    IO.puts "Continuing download"
    p
  end
  
  defp finish_download({ client, total_size, size, file } = p) do
    IO.puts "Finished download"
    nil
  end
end