Remove no-longer-necessary setup callback cross-thread task (#341)

Co-authored-by: Bret Ambrose <[email protected]>

source/v5/mqtt5_client.c

@@ -697,30 +697,6 @@ static void s_aws_mqtt5_client_shutdown_channel_clean(
     aws_mqtt5_operation_disconnect_release(disconnect_op);
 }
 
-struct aws_mqtt5_shutdown_task {
-    struct aws_task task;
-    struct aws_allocator *allocator;
-    int error_code;
-    struct aws_mqtt5_client *client;
-};
-
-static void s_mqtt5_client_shutdown_final(int error_code, struct aws_mqtt5_client *client);
-
-static void s_shutdown_task_fn(struct aws_task *task, void *arg, enum aws_task_status status) {
-    (void)task;
-
-    struct aws_mqtt5_shutdown_task *shutdown_task = arg;
-    if (status != AWS_TASK_STATUS_RUN_READY) {
-        goto done;
-    }
-
-    s_mqtt5_client_shutdown_final(shutdown_task->error_code, shutdown_task->client);
-
-done:
-
-    aws_mem_release(shutdown_task->allocator, shutdown_task);
-}
-
 static void s_mqtt5_client_shutdown_final(int error_code, struct aws_mqtt5_client *client) {
 
     AWS_FATAL_ASSERT(aws_event_loop_thread_is_callers_thread(client->loop));
@@ -764,19 +740,8 @@ static void s_mqtt5_client_shutdown(
         error_code = AWS_ERROR_MQTT_UNEXPECTED_HANGUP;
     }
 
-    if (aws_event_loop_thread_is_callers_thread(client->loop)) {
-        s_mqtt5_client_shutdown_final(error_code, client);
-        return;
-    }
-
-    struct aws_mqtt5_shutdown_task *shutdown_task =
-        aws_mem_calloc(client->allocator, 1, sizeof(struct aws_mqtt5_shutdown_task));
-
-    aws_task_init(&shutdown_task->task, s_shutdown_task_fn, (void *)shutdown_task, "ShutdownTask");
-    shutdown_task->allocator = client->allocator;
-    shutdown_task->client = client;
-    shutdown_task->error_code = error_code;
-    aws_event_loop_schedule_task_now(client->loop, &shutdown_task->task);
+    AWS_FATAL_ASSERT(aws_event_loop_thread_is_callers_thread(client->loop));
+    s_mqtt5_client_shutdown_final(error_code, client);
 }
 
 static void s_mqtt5_client_setup(