// SPDX-License-Identifier: Apache-2.0
// Copyright (c) 2026 ReifyDB
//! Always-on profiler primitives over `tracing`: `ProfilerLayer` appends a fixed-size `MinimalSpanRecord` per
//! matching span without allocating on the hot path, and `ScopeHandle::finish` drains them to a `ProfilerSink`.
//!
//! Deliberately free of metric and IoC dependencies, so tests can embed the layer with a `NoopSink` and the data
//! model is usable without pulling in the subsystem.