Function enabled 

pub fn enabled() -> bool

The perf-trace feature is off: perf instrumentation is compiled out of this build, so the switch is a compile-time false constant — no OnceLock, no environment read. #[inline] so every downstream if enabled() branch constant-folds to nothing, taking the frust-perf emission (and its strings) with it via LLVM dead-code elimination. Build with --features perf-trace (what a debug/profile build does) to restore the runtime FRUST_TRACE switch documented above.