docs: mention record on start

Author: DeltaNeverUsed

README.md

@@ -9,4 +9,6 @@ Profiling tool for UdonSharpd
 5. Press ``O`` to start recording.
 6. Press ``P`` to stop recording. Be patient after pressing, depending on the size, it might take a couple seconds to process all the events.
 7. Create a trace file by going to ``Tools/UdonSharpProfiler/Save Unity`` Log or ``Tools/UdonSharpProfiler/Save VRChat Log``
-8. Load the file into [Perfetto](https://ui.perfetto.dev/).
+8. Load the file into [Perfetto](https://ui.perfetto.dev/).
+
+By default it won't be recording until you press ``O``. You can tell it to start recording as soon as the game starts but toggling the ``recording`` boolean on the Profiler game object.