Function note_tool_call_trace 

pub fn note_tool_call_trace(
    name: &str,
    root: &Path,
    channel: u16,
    corr: u64,
    phases: ToolCallPhaseDurations,
)

Record a completed subc tool call for slow-call diagnostics and the standing perf-tick window. The writer calls this only after write_all has handed the complete response frame to the transport.