Add amqp_gen_consumer behaviour implementation (#190)

lib/amqp/channel.ex

@@ -21,7 +21,7 @@ defmodule Amqpx.Channel do
 
   @spec open(Connection.t(), pid()) :: {:ok, Channel.t()} | {:error, any}
   def open(%Connection{pid: pid} = conn, consumer_pid) do
-    case :amqp_connection.open_channel(pid, {:amqp_direct_consumer, [consumer_pid]}) do
+    case :amqp_connection.open_channel(pid, {Amqpx.DirectConsumer, [consumer_pid]}) do
       {:ok, chan_pid} -> {:ok, %Channel{conn: conn, pid: chan_pid}}
       error -> error
     end

lib/amqp/direct_consumer.ex

@@ -0,0 +1,46 @@
+defmodule Amqpx.DirectConsumer do
+  @moduledoc """
+  This module "wraps" the [amqp_direct_consumer](https://github.com/rabbitmq/rabbitmq-server/blob/main/deps/amqp_client/src/amqp_direct_consumer.erl) module to manage the race condition that occurs at supervisor shutdown, leading to error logs such as:
+  ```
+  [error] GenServer #PID<0.846.0> terminating
+  ** (stop) {:error, {:consumer_died, :shutdown}}
+  Last message: {:DOWN, #Reference<0.1010163881.3799777283.106124>, :process, #PID<0.798.0>, :shutdown}.
+  ```
+  The reason for this behavior is that the `amqp_direct_consumer` module considers any exit reason other than `:normal` as an error, prompting it to exit.
+  In our implementation, we have introduced two pattern matches to treat the exit reasons `:shutdown` and `{:shutdown, reason}` as normal occurrences; these conditions typically arise when the supervisor terminates the consumer, such as during a standard shutdown of the application."
+  """
+
+  @behaviour :amqp_gen_consumer
+
+  defdelegate init(opts), to: :amqp_direct_consumer
+
+  defdelegate handle_consume(m, a, c), to: :amqp_direct_consumer
+
+  defdelegate handle_consume_ok(m, a, c), to: :amqp_direct_consumer
+
+  defdelegate handle_cancel(m, c), to: :amqp_direct_consumer
+
+  defdelegate handle_cancel_ok(m, a, c), to: :amqp_direct_consumer
+
+  defdelegate handle_server_cancel(m, c), to: :amqp_direct_consumer
+
+  defdelegate handle_deliver(m, a, c), to: :amqp_direct_consumer
+
+  defdelegate handle_deliver(m, a, delivery_ctx, c), to: :amqp_direct_consumer
+
+  defdelegate handle_call(m, a, c), to: :amqp_direct_consumer
+
+  defdelegate terminate(reason, c), to: :amqp_direct_consumer
+
+  def handle_info({:DOWN, _mref, :process, c, :shutdown}, c) do
+    {:ok, c}
+  end
+
+  def handle_info({:DOWN, _mref, :process, c, {:shutdown, _}}, c) do
+    {:ok, c}
+  end
+
+  def handle_info(m, c) do
+    :amqp_direct_consumer.handle_info(m, c)
+  end
+end