log, timer: add LOG_TIME_MILLIS_WITH_CATEGORY_MSG_ONCE macro

that prints the descriptive message when logging the start
but not when logging the completion.

Author: jonatack

src/logging/timer.h

@@ -100,6 +100,8 @@ class Timer
     BCLog::Timer<std::chrono::microseconds> PASTE2(logging_timer, __COUNTER__)(__func__, end_msg, log_category)
 #define LOG_TIME_MILLIS_WITH_CATEGORY(end_msg, log_category) \
     BCLog::Timer<std::chrono::milliseconds> PASTE2(logging_timer, __COUNTER__)(__func__, end_msg, log_category)
+#define LOG_TIME_MILLIS_WITH_CATEGORY_MSG_ONCE(end_msg, log_category) \
+    BCLog::Timer<std::chrono::milliseconds> PASTE2(logging_timer, __COUNTER__)(__func__, end_msg, log_category, /* msg_on_completion=*/false)
 #define LOG_TIME_SECONDS(end_msg) \
     BCLog::Timer<std::chrono::seconds> PASTE2(logging_timer, __COUNTER__)(__func__, end_msg)