When an event is slow, know where the time went — not just that the overall handler took 500ms, but which function inside it was responsible, and which functions that function called.

Most driver events are a tree of function calls: an event handler calls a few helpers, those call C4 API methods, some branches are fast, others aren't. Without profiling, that tree is invisible — all you see is a single duration for the outer handler.

Method-level profiling captures the full call tree for an individual event. You can view it as a flame graph (the hot paths stand out visually), as a waterfall chart (good for understanding when in the event each call happened), or as a collapsible call tree (good for reading the code path, especially when exploring unfamiliar code).

Because capturing that much detail has overhead, profiling is opt-in. You turn it on when investigating a specific problem or when you want to understand an event's shape, and turn it off when you're done.