Basically, a program illustrating the back pressure problem mentioned in http://erlang.org/pipermail/erlang-questions/2014-November/081843.html

Run it using erl +S1 -noshell -eval 'back_pressure:main(0), halt(0).. In htop, it shows unbounded memory grow (due to the growing of unbounded mailbox). Nonsuprisingly, after removing sleep, the memeory stays constant.

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-module(back_pressure).
-mode(compile).
-compile(export_all).

consumer() ->
  receive _ -> ok end,
  timer:sleep(1000),
  consumer().

producer(C) ->
  C ! 0,
  producer(C).

main(_) ->
  C = spawn(fun consumer/0),
  producer(C),
  ok.