diff --git a/src/hubclient.cpp b/src/hubclient.cpp
index 5933b7d..a99b73a 100644
--- a/src/hubclient.cpp
+++ b/src/hubclient.cpp
@@ -1,6 +1,6 @@
 #include "hubclient.h"
 
-namespace msghublib { namespace detail {
+namespace msghublib::detail {
     using boost::asio::ip::tcp;
 
     auto hubclient::bind(void (hubclient::*handler)(error_code)) {
@@ -29,7 +29,7 @@ namespace msghublib { namespace detail {
 
     void hubclient::write(const hubmessage& msg)
     {
-        post(socket_.get_executor(), [this, msg, self=shared_from_this()]{
+        post(socket_.get_executor(), [this, msg, self=shared_from_this()] () mutable {
             bool write_in_progress = !outmsg_queue_.empty();
             outmsg_queue_.push_back(std::move(msg));
             if (!write_in_progress)
@@ -48,7 +48,7 @@ namespace msghublib { namespace detail {
             async_read(socket_, inmsg_.payload_area(), bind(&hubclient::handle_read_body));
         }
 
-        // TODO handle invalid headers (connection reset?)
+        // TODO(sehe): handle invalid headers (connection reset?)
     }
 
     void hubclient::handle_read_body(error_code error)
@@ -59,7 +59,7 @@ namespace msghublib { namespace detail {
             // Get next
             async_read(socket_, inmsg_.header_buf(), bind(&hubclient::handle_read_header));
         }
-        // TODO handle IO failure
+        // TODO(sehe): handle IO failure
     }
 
     void hubclient::handle_write(error_code error)
@@ -68,7 +68,8 @@ namespace msghublib { namespace detail {
             outmsg_queue_.pop_front();
 
             if (!outmsg_queue_.empty()) {
-                // Write next from queue // TODO remove duplication
+                // Write next from queue
+                // TODO(sehe) remove duplication
                 async_write(socket_,
                     outmsg_queue_.front().on_the_wire(),
                     bind(&hubclient::handle_write));
@@ -77,4 +78,4 @@ namespace msghublib { namespace detail {
         // error TODO handling
     }
 
-} }
+}  // namespace msghublib::detail
diff --git a/src/hubclient.h b/src/hubclient.h
index 12d6346..a226c13 100644
--- a/src/hubclient.h
+++ b/src/hubclient.h
@@ -27,16 +27,17 @@ class hubclient : public std::enable_shared_from_this<hubclient>
 	void write(const hubmessage& msg);
   private:
     using error_code = boost::system::error_code;
-	void handle_read_header(error_code);
-	void handle_read_body(error_code);
-	void handle_write(error_code);
+	void handle_read_header(error_code /*error*/);
+	void handle_read_body(error_code /*error*/);
+	void handle_write(error_code /*error*/);
 
-    auto bind(void (hubclient::*)(error_code));
-  private:
+    auto bind(void (hubclient::* /*handler*/)(error_code));
+  
 	tcp::socket			socket_;
 	ihub&				distributor_;
 	hubmessage			inmsg_;
 	hubmessage_queue	outmsg_queue_;
 };
 
-} }
+}  // namespace detail
+}  // namespace msghublib
diff --git a/src/hubconnection.cpp b/src/hubconnection.cpp
index ba55b4d..2a5f6b1 100644
--- a/src/hubconnection.cpp
+++ b/src/hubconnection.cpp
@@ -1,6 +1,6 @@
 #include "hubconnection.h"
 
-namespace msghublib { namespace detail {
+namespace msghublib::detail {
     using boost::asio::ip::tcp;
 
     auto hubconnection::bind(void (hubconnection::*handler)(error_code)) {
@@ -42,7 +42,7 @@ namespace msghublib { namespace detail {
             else
             {
 #pragma GCC diagnostic ignored "-Wdeprecated" // implicit this-capture
-                post(socket_.get_executor(), [=, self=shared_from_this()]
+                post(socket_.get_executor(), [=, self=shared_from_this()] () mutable
                     { do_write(std::move(msg)); });
             }
             return true;
@@ -118,7 +118,7 @@ namespace msghublib { namespace detail {
     {
         is_closing = true; // atomic
 
-        // TODO: Unsubscribe?
+        // TODO(sehe): Unsubscribe?
 
         if (forced || outmsg_queue_.empty()) {
             if (socket_.is_open()) {
@@ -128,4 +128,4 @@ namespace msghublib { namespace detail {
         }
     }
 
-} }
+} // namespace msghublib::detail
diff --git a/src/hubconnection.h b/src/hubconnection.h
index 51f0ab1..9c7a969 100644
--- a/src/hubconnection.h
+++ b/src/hubconnection.h
@@ -29,7 +29,7 @@ class hubconnection : public std::enable_shared_from_this<hubconnection>
 
 private:
     using error_code = boost::system::error_code;
-    auto bind(void (hubconnection::*)(error_code));
+    auto bind(void (hubconnection::* /*handler*/)(error_code));
 
 	void handle_read_header(error_code error);
 	void handle_read_body(error_code error);
@@ -37,7 +37,6 @@ class hubconnection : public std::enable_shared_from_this<hubconnection>
 	void handle_write(error_code error);
 	void do_close(bool forced);
 
-private:
 	tcp::socket        socket_;
 	ihub&              courier_;
 	hubmessage         inmsg_;
@@ -45,4 +44,5 @@ class hubconnection : public std::enable_shared_from_this<hubconnection>
 	boost::atomic_bool is_closing;
 };
 
-} }
+}  // namespace detail
+}  // namespace msghublib
diff --git a/src/hubmessage.cpp b/src/hubmessage.cpp
index 0d864bb..0243d79 100644
--- a/src/hubmessage.cpp
+++ b/src/hubmessage.cpp
@@ -15,7 +15,7 @@ namespace msghublib {
         headers_.msgaction = action_;
         headers_.magic     = cookie;
 
-        auto out = payload_.data();
+        auto *out = payload_.data();
         out = std::copy_n(topic.data(), topic.size(), out);
         out = std::copy_n(msg.data(),   msg.size(),   out);
     }
@@ -41,4 +41,4 @@ namespace msghublib {
             .substr(headers_.topiclen, headers_.bodylen);
     }
 
-}
+}  // namespace msghublib
diff --git a/src/hubmessage.h b/src/hubmessage.h
index fd7f130..4c97aa5 100644
--- a/src/hubmessage.h
+++ b/src/hubmessage.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <boost/asio/buffer.hpp>
 #include <functional>
 #include <string_view>
 
@@ -12,18 +13,20 @@ namespace msghublib {
 class hubmessage
 {
   public:
+    // the following affect on-the-wire compatiblity
 	enum action : char { subscribe, unsubscribe, publish };
 	enum { version = 0x1 };
 	enum { cookie = 0xF00D ^ (version << 8) };
 	enum { messagesize = 0x2000 };
+    // the following does NOT affect on-the-wire compatiblity
+    enum { preallocated = 196 };
 
     hubmessage(action a={}, std::string_view topic={}, span<char const> msg = {});
 
-	bool             verify()     const;
-
-	action           get_action() const;
-	std::string_view topic()      const;
-	span<char const> body()       const;
+	[[nodiscard]] bool             verify()     const;
+	[[nodiscard]] action           get_action() const;
+	[[nodiscard]] std::string_view topic()      const;
+	[[nodiscard]] span<char const> body()       const;
 
   private:
 	#pragma pack(push, 1)
@@ -36,7 +39,7 @@ class hubmessage
 	#pragma pack(pop)
 
     headers_t headers_;
-    boost::container::small_vector<char, 242> payload_;
+    boost::container::small_vector<char, preallocated> payload_;
 
   public:
     // input buffer views
@@ -50,14 +53,14 @@ class hubmessage
     }
 
     // output buffer views
-    auto on_the_wire() const {
-        return std::vector { 
+    [[nodiscard]] auto on_the_wire() const {
+        return std::array<boost::asio::const_buffer, 2> { 
             boost::asio::buffer(&headers_, sizeof(headers_)),
             boost::asio::buffer(payload_.data(), payload_.size())
         };
     }
 };
 
-typedef std::deque<hubmessage> hubmessage_queue;
+using hubmessage_queue = std::deque<hubmessage>;
 
-}
+}  // namespace msghublib
diff --git a/src/ihub.h b/src/ihub.h
index a525460..77e2cda 100644
--- a/src/ihub.h
+++ b/src/ihub.h
@@ -15,4 +15,4 @@ namespace msghublib {
             virtual void deliver(hubmessage const& msg) = 0;
         };
     }
-}
+}  // namespace msghublib
diff --git a/src/msghub.cpp b/src/msghub.cpp
index 8596de2..c59bb5e 100644
--- a/src/msghub.cpp
+++ b/src/msghub.cpp
@@ -1,5 +1,7 @@
 #include "msghub.h"
 
+#include <utility>
+
 #include "hubclient.h"
 #include "hubconnection.h"
 #include "ihub.h"
@@ -28,7 +30,7 @@ namespace msghublib {
         std::multimap<std::string, std::weak_ptr<hubclient>> remote_subs_;
 
       public:
-        impl(boost::asio::any_io_executor executor)
+        explicit impl(boost::asio::any_io_executor const& executor)
             : executor_(executor)
             , acceptor_(make_strand(executor))
         {}
@@ -36,25 +38,20 @@ namespace msghublib {
         void stop() {
             {
                 std::shared_ptr<hubconnection> rhub;
-                if (auto p = std::atomic_exchange(&remote_hub_, rhub))
+                if (auto p = std::atomic_exchange(&remote_hub_, rhub)) {
                     p->close(false);
+                }
             }
 
             if (!weak_from_this().expired()) {
-                post(acceptor_.get_executor(), [this, self = shared_from_this()] {
-                    if (acceptor_.is_open())
-                        acceptor_.cancel();
-                });
-            } else {
-                if (acceptor_.is_open())
-                    acceptor_.cancel();
-            }
-
-            if (0) {
-                std::lock_guard lk(mutex_);
-                for (auto& [_, client] : remote_subs_)
-                    if (auto alive = client.lock())
-                        alive->stop();
+                post(acceptor_.get_executor(),
+                     [this, self = shared_from_this()] {
+                         if (acceptor_.is_open()) {
+                             acceptor_.cancel();
+                         }
+                     });
+            } else if (acceptor_.is_open()) {
+                acceptor_.cancel();
             }
 
             work_.reset();
@@ -114,13 +111,13 @@ namespace msghublib {
             return false;
         }
 
-        bool subscribe(const std::string& topic, msghub::onmessage handler) {
+        bool subscribe(const std::string& topic, const msghub::onmessage& handler) {
             std::unique_lock lk(mutex_);
             if (auto [it, ins] = local_subs_.emplace(topic, handler); ins) {
                 lk.unlock();
                 if (auto p = atomic_load(&remote_hub_)) {
                     return p->write({ hubmessage::action::subscribe, topic }, true);
-                    // TODO: wait feedback from server here?
+                    // TODO(sehe): wait feedback from server here?
                 }
             } else {
                 // just update the handler
@@ -133,7 +130,7 @@ namespace msghublib {
 
       private:
         msghub::onmessage const& lookup_handler(std::string_view topic) const {
-            static const msghub::onmessage no_handler = [](auto...) {};
+            static const msghub::onmessage no_handler = [](auto... /*unused*/) {};
 
             std::lock_guard lk(mutex_);
             auto it = local_subs_.find(std::string(topic));
@@ -141,7 +138,7 @@ namespace msghublib {
         }
 
         void distribute(std::shared_ptr<hubclient> const& subscriber,
-                        hubmessage const& msg) {
+                        hubmessage const& msg) override {
             std::string topic(msg.topic());
             std::unique_lock lk(mutex_);
             auto range = remote_subs_.equal_range(topic);
@@ -152,8 +149,9 @@ namespace msghublib {
                     if (auto alive = it->second.lock()) {
                         alive->write(msg);
                         ++it;
-                    } else
+                    } else {
                         it = remote_subs_.erase(it);
+                    }
                 }
                 break;
 
@@ -168,10 +166,11 @@ namespace msghublib {
             case hubmessage::action::unsubscribe:
                 for (auto it = range.first; it != range.second;) {
                     if (auto alive = it->second.lock();
-                        !alive || alive == subscriber)
+                        !alive || alive == subscriber) {
                         it = remote_subs_.erase(it);
-                    else
+                    } else {
                         ++it;
+                    }
                 }
                 break;
 
@@ -180,7 +179,7 @@ namespace msghublib {
             }
         }
 
-        void deliver(hubmessage const& msg) {
+        void deliver(hubmessage const& msg) override {
             lookup_handler(msg.topic())(msg.topic(), msg.body());
         }
 
@@ -221,7 +220,7 @@ namespace msghublib {
     bool msghub::connect(const std::string& hostip, uint16_t port)         { return pimpl->connect(hostip, port);     } 
     bool msghub::create(uint16_t port)                                     { return pimpl->create(port);              } 
     bool msghub::unsubscribe(const std::string& topic)                     { return pimpl->unsubscribe(topic);        } 
-    bool msghub::subscribe(const std::string& topic, onmessage handler)    { return pimpl->subscribe(topic, handler); } 
+    bool msghub::subscribe(const std::string& topic, onmessage handler)    { return pimpl->subscribe(topic, std::move(handler)); } 
     bool msghub::publish(std::string_view topic, span<char const> message) { return pimpl->publish(topic, message);   } 
 
 } // namespace msghublib
diff --git a/test/main.cpp b/test/main.cpp
index 78bd280..baf95bc 100644
--- a/test/main.cpp
+++ b/test/main.cpp
@@ -15,9 +15,9 @@ void test_server_oncleintfailure();
 void test_toobigmsg();
 void test_emptymsg();
 
-test_suite* init_unit_test_suite(int, char**)
+test_suite* init_unit_test_suite(int /*unused*/, char** /*unused*/)
 {
-	test_suite *test = BOOST_TEST_SUITE("messagehub test");
+	auto *test = BOOST_TEST_SUITE("messagehub test");
 
 	test->add(BOOST_TEST_CASE(&test_create));
 	test->add(BOOST_TEST_CASE(&test_connect));
diff --git a/test/subscribe.cpp b/test/subscribe.cpp
index 3cc39b8..e476bc1 100644
--- a/test/subscribe.cpp
+++ b/test/subscribe.cpp
@@ -28,7 +28,7 @@ namespace {
         BOOST_TEST(expected == message, boost::test_tools::per_element());
         newmessage.notify_one();
     }
-}
+}  // namespace
 
 void test_subscribe()
 {