piano vs metrics-lib vs benchmark

Automatic instrumentation-based profiler for Rust. Measures self-time, call counts, and heap allocations per function.

The fastest metrics library for Rust. Lock-free 0.6ns gauges, 18ns counters, timers, rate meters, async timing, adaptive sampling, and system health. Cross-platform with minimal dependencies.

Nanosecond-precision benchmarking for dev, testing, and production. Zero-overhead core timing when disabled; optional std-powered collectors and zero-dependency metrics (Watch/Timer) for real service observability.