add WallTime và WallTimer

CMakeLists.txt

@@ -52,6 +52,7 @@ add_library(${PROJECT_NAME} SHARED
   src/rate.cpp
   src/time.cpp
   src/timer.cpp
+  src/wall_timer.cpp
 )
 
 if(BUILDING_WITH_CATKIN)
@@ -151,3 +152,12 @@ if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/test/duration.cpp)
     GTest::Main
   )
 endif()
+
+# Standalone WallTime test (header-only)
+if(EXISTS ${CMAKE_CURRENT_SOURCE_DIR}/test/walltime_standalone_test.cpp)
+  add_executable(${PROJECT_NAME}_walltime_standalone_test test/walltime_standalone_test.cpp)
+  target_include_directories(${PROJECT_NAME}_walltime_standalone_test PRIVATE
+    ${CMAKE_CURRENT_SOURCE_DIR}/include
+  )
+  target_compile_features(${PROJECT_NAME}_walltime_standalone_test PUBLIC cxx_std_17)
+endif()