feat(app): add concurrent message queue

tests/app/helpers/thread_test_utils.cpp

@@ -0,0 +1,23 @@
+#include "thread_test_utils.hpp"
+
+#include <cassert>
+#include <cstddef>
+#include <thread>
+
+namespace app::tests::helpers {
+
+std::thread createProducer(MessageQueue &queue, std::size_t threadIndex,
+                           std::size_t messagesCount) {
+  return std::thread([&queue, threadIndex, messagesCount]() {
+    for (std::size_t messageIndex = 0; messageIndex < messagesCount;
+         ++messageIndex) {
+      queue.push({
+          logger::LogLevel::info(),
+          "Thread " + std::to_string(threadIndex) + ", message " +
+              std::to_string(messageIndex),
+      });
+    }
+  });
+}
+
+} // namespace app::tests::helpers

tests/app/helpers/thread_test_utils.hpp

@@ -0,0 +1,13 @@
+#pragma once
+
+#include <cstddef>
+#include <thread>
+
+#include "message_queue.hpp"
+
+namespace app::tests::helpers {
+
+std::thread createProducer(MessageQueue &queue, std::size_t threadIndex,
+                           std::size_t messagesCount);
+
+} // namespace app::tests::helpers