switch to coroutine execution model

src/ProxyCommands.hh

@@ -1,15 +1,6 @@
 #pragma once
 
-#include <stdint.h>
+#include "Client.hh"
 
-#include <string>
-
-#include "ProxyServer.hh"
-#include "ServerState.hh"
-
-void on_proxy_command(
-    std::shared_ptr<ProxyServer::LinkedSession> ses,
-    bool from_server,
-    uint16_t command,
-    uint32_t flag,
-    std::string& data);
+asio::awaitable<void> on_proxy_command(std::shared_ptr<Client> c, bool from_server, std::unique_ptr<Channel::Message> msg);
+asio::awaitable<void> handle_proxy_server_commands(std::shared_ptr<Client> c, std::shared_ptr<ProxySession> ses, std::shared_ptr<Channel> channel);