diff --git a/include/spdlog/async_logger.h b/include/spdlog/async_logger.h
index 73f34ced..a7ecb787 100644
--- a/include/spdlog/async_logger.h
+++ b/include/spdlog/async_logger.h
@@ -58,7 +58,7 @@ public:
     std::shared_ptr<logger> clone(std::string new_name) override;
 
 protected:
-    void sink_it_(const details::log_msg &msg) override;
+    void sink_it_(details::log_msg &msg) override;
     void flush_() override;
 
     void backend_log_(const details::log_msg &incoming_log_msg);
diff --git a/include/spdlog/details/async_logger_impl.h b/include/spdlog/details/async_logger_impl.h
index 2923a10e..e604d4ed 100644
--- a/include/spdlog/details/async_logger_impl.h
+++ b/include/spdlog/details/async_logger_impl.h
@@ -36,14 +36,14 @@ inline spdlog::async_logger::async_logger(
 }
 
 // send the log message to the thread pool
-inline void spdlog::async_logger::sink_it_(const details::log_msg &msg)
+inline void spdlog::async_logger::sink_it_(details::log_msg &msg)
 {
 #if defined(SPDLOG_ENABLE_MESSAGE_COUNTER)
     incr_msg_counter_(msg);
 #endif
     if (auto pool_ptr = thread_pool_.lock())
     {
-        pool_ptr->post_log(shared_from_this(), msg, overflow_policy_);
+        pool_ptr->post_log(shared_from_this(), std::move(msg), overflow_policy_);
     }
     else
     {
diff --git a/include/spdlog/details/log_msg.h b/include/spdlog/details/log_msg.h
index 3894b0a4..f94aa7f4 100644
--- a/include/spdlog/details/log_msg.h
+++ b/include/spdlog/details/log_msg.h
@@ -39,8 +39,9 @@ struct log_msg
     log_clock::time_point time;
     size_t thread_id;
     fmt::memory_buffer raw;
-    mutable size_t msg_id{0};
-    // info about wrapping the formatted text with color
+    size_t msg_id{0};
+
+    // info about wrapping the formatted text with color (updated by pattern_formatter).
     mutable size_t color_range_start{0};
     mutable size_t color_range_end{0};
 };
diff --git a/include/spdlog/details/logger_impl.h b/include/spdlog/details/logger_impl.h
index 27f0eb46..46301ea1 100644
--- a/include/spdlog/details/logger_impl.h
+++ b/include/spdlog/details/logger_impl.h
@@ -317,7 +317,7 @@ inline bool spdlog::logger::should_log(spdlog::level::level_enum msg_level) cons
 // protected virtual called at end of each user log call (if enabled) by the
 // line_logger
 //
-inline void spdlog::logger::sink_it_(const details::log_msg &msg)
+inline void spdlog::logger::sink_it_(details::log_msg &msg)
 {
 #if defined(SPDLOG_ENABLE_MESSAGE_COUNTER)
     incr_msg_counter_(msg);
diff --git a/include/spdlog/details/thread_pool.h b/include/spdlog/details/thread_pool.h
index 64dc6a26..9107cd1b 100644
--- a/include/spdlog/details/thread_pool.h
+++ b/include/spdlog/details/thread_pool.h
@@ -69,7 +69,7 @@ struct async_msg
 #endif
 
     // construct from log_msg with given type
-    async_msg(async_logger_ptr &&worker, async_msg_type the_type, const details::log_msg &m)
+    async_msg(async_logger_ptr &&worker, async_msg_type the_type, details::log_msg &&m)
         : msg_type(the_type)
         , level(m.level)
         , time(m.time)
@@ -149,9 +149,9 @@ public:
     thread_pool(const thread_pool &) = delete;
     thread_pool &operator=(thread_pool &&) = delete;
 
-    void post_log(async_logger_ptr &&worker_ptr, const details::log_msg &msg, async_overflow_policy overflow_policy)
+    void post_log(async_logger_ptr &&worker_ptr, details::log_msg &&msg, async_overflow_policy overflow_policy)
     {
-        async_msg async_m(std::forward<async_logger_ptr>(worker_ptr), async_msg_type::log, msg);
+        async_msg async_m(std::forward<async_logger_ptr>(worker_ptr), async_msg_type::log, std::forward<log_msg>(msg));
         post_async_msg_(std::move(async_m), overflow_policy);
     }
 
diff --git a/include/spdlog/logger.h b/include/spdlog/logger.h
index 13ef910f..1bcf4bc2 100644
--- a/include/spdlog/logger.h
+++ b/include/spdlog/logger.h
@@ -142,7 +142,7 @@ public:
     virtual std::shared_ptr<logger> clone(std::string logger_name);
 
 protected:
-    virtual void sink_it_(const details::log_msg &msg);
+    virtual void sink_it_(details::log_msg &msg);
     virtual void flush_();
 
     bool should_flush_(const details::log_msg &msg);
diff --git a/tests/includes.h b/tests/includes.h
index bce67418..2090bcb4 100644
--- a/tests/includes.h
+++ b/tests/includes.h
@@ -12,6 +12,7 @@
 
 #define SPDLOG_TRACE_ON
 #define SPDLOG_DEBUG_ON
+#define SPDLOG_ENABLE_MESSAGE_COUNTER
 
 #include "spdlog/async.h"
 #include "spdlog/sinks/basic_file_sink.h"
diff --git a/tests/test_misc.cpp b/tests/test_misc.cpp
index 22dfb4b8..66ae7c87 100644
--- a/tests/test_misc.cpp
+++ b/tests/test_misc.cpp
@@ -175,3 +175,19 @@ TEST_CASE("to_hex_no_delimiter", "[to_hex]")
     auto output = oss.str();
     REQUIRE(ends_with(output, "0000: 090A0B0CFFFF" + std::string(spdlog::details::os::default_eol)));
 }
+
+TEST_CASE("message_counter", "[message_counter]")
+{
+    std::ostringstream oss;
+    auto oss_sink = std::make_shared<spdlog::sinks::ostream_sink_mt>(oss);
+    spdlog::logger oss_logger("oss", oss_sink);
+    oss_logger.set_pattern("%i %v");
+
+    oss_logger.info("Hello");
+    REQUIRE(oss.str() == "000001 Hello" + std::string(spdlog::details::os::default_eol));
+
+    oss.str("");
+    oss_logger.info("Hello again");
+
+    REQUIRE(oss.str() == "000002 Hello again" + std::string(spdlog::details::os::default_eol));
+}