Support GenStage v1.2.0

lib/broadway/topology/producer_stage.ex

@@ -17,12 +17,6 @@ defmodule Broadway.Topology.ProducerStage do
 
   @spec drain(GenServer.server()) :: :ok
   def drain(producer) do
-    # First we set the demand to accumulate. This is to avoid
-    # polling implementations from re-entering the polling loop
-    # once they flush any timers during draining. Push implementations
-    # will still empty out their queues as long as they put them
-    # in the GenStage buffer.
-    GenStage.demand(producer, :accumulate)
     GenStage.cast(producer, {__MODULE__, :prepare_for_draining})
     GenStage.async_info(producer, {__MODULE__, :cancel_consumers})
   end

mix.lock

@@ -3,7 +3,7 @@
   "earmark_parser": {:hex, :earmark_parser, "1.4.39", "424642f8335b05bb9eb611aa1564c148a8ee35c9c8a8bba6e129d51a3e3c6769", [:mix], [], "hexpm", "06553a88d1f1846da9ef066b87b57c6f605552cfbe40d20bd8d59cc6bde41944"},
   "ex_doc": {:hex, :ex_doc, "0.34.0", "ab95e0775db3df71d30cf8d78728dd9261c355c81382bcd4cefdc74610bef13e", [:mix], [{:earmark_parser, "~> 1.4.39", [hex: :earmark_parser, repo: "hexpm", optional: false]}, {:makeup_c, ">= 0.1.0", [hex: :makeup_c, repo: "hexpm", optional: true]}, {:makeup_elixir, "~> 0.14 or ~> 1.0", [hex: :makeup_elixir, repo: "hexpm", optional: false]}, {:makeup_erlang, "~> 0.1 or ~> 1.0", [hex: :makeup_erlang, repo: "hexpm", optional: false]}, {:makeup_html, ">= 0.1.0", [hex: :makeup_html, repo: "hexpm", optional: true]}], "hexpm", "60734fb4c1353f270c3286df4a0d51e65a2c1d9fba66af3940847cc65a8066d7"},
   "excoveralls": {:hex, :excoveralls, "0.18.1", "a6f547570c6b24ec13f122a5634833a063aec49218f6fff27de9df693a15588c", [:mix], [{:castore, "~> 1.0", [hex: :castore, repo: "hexpm", optional: true]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "d65f79db146bb20399f23046015974de0079668b9abb2f5aac074d078da60b8d"},
-  "gen_stage": {:hex, :gen_stage, "1.0.0", "51c8ae56ff54f9a2a604ca583798c210ad245f415115453b773b621c49776df5", [:mix], [], "hexpm", "1d9fc978db5305ac54e6f5fec7adf80cd893b1000cf78271564c516aa2af7706"},
+  "gen_stage": {:hex, :gen_stage, "1.2.1", "19d8b5e9a5996d813b8245338a28246307fd8b9c99d1237de199d21efc4c76a1", [:mix], [], "hexpm", "83e8be657fa05b992ffa6ac1e3af6d57aa50aace8f691fcf696ff02f8335b001"},
   "jason": {:hex, :jason, "1.4.1", "af1504e35f629ddcdd6addb3513c3853991f694921b1b9368b0bd32beb9f1b63", [:mix], [{:decimal, "~> 1.0 or ~> 2.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "fbb01ecdfd565b56261302f7e1fcc27c4fb8f32d56eab74db621fc154604a7a1"},
   "makeup": {:hex, :makeup, "1.1.2", "9ba8837913bdf757787e71c1581c21f9d2455f4dd04cfca785c70bbfff1a76a3", [:mix], [{:nimble_parsec, "~> 1.2.2 or ~> 1.3", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "cce1566b81fbcbd21eca8ffe808f33b221f9eee2cbc7a1706fc3da9ff18e6cac"},
   "makeup_elixir": {:hex, :makeup_elixir, "0.16.2", "627e84b8e8bf22e60a2579dad15067c755531fea049ae26ef1020cad58fe9578", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}, {:nimble_parsec, "~> 1.2.3 or ~> 1.3", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "41193978704763f6bbe6cc2758b84909e62984c7752b3784bd3c218bb341706b"},