feat(Core/Common): add Asio network threading (#6063)

src/common/Asio/AsioHacksFwd.h

@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2016+ AzerothCore <www.azerothcore.org>, released under GNU AGPL v3 license: https://github.com/azerothcore/azerothcore-wotlk/blob/master/LICENSE-AGPL3
+ * Copyright (C) 2021+ WarheadCore <https://github.com/WarheadCore>
+ */
+
+#ifndef AsioHacksFwd_h__
+#define AsioHacksFwd_h__
+
+#include <boost/version.hpp>
+
+/**
+  Collection of forward declarations to improve compile time
+ */
+namespace boost::posix_time
+{
+    class ptime;
+}
+
+namespace boost::asio
+{
+    template <typename Time>
+    struct time_traits;
+}
+
+namespace boost::asio::ip
+{
+    class address;
+    class tcp;
+
+    template <typename InternetProtocol>
+    class basic_endpoint;
+
+    typedef basic_endpoint<tcp> tcp_endpoint;
+}
+
+namespace acore::Asio
+{
+    class DeadlineTimer;
+    class IoContext;
+    class Resolver;
+    class Strand;
+}
+
+#endif // AsioHacksFwd_h__