tracing capture interface

Signed-off-by: Jason Volk <jason@zemos.net>

src/core/log/capture/guard.rs

@@ -0,0 +1,12 @@
+use std::sync::Arc;
+
+use super::Capture;
+
+/// Capture instance scope guard.
+pub struct Guard {
+	pub(super) capture: Arc<Capture>,
+}
+
+impl Drop for Guard {
+	fn drop(&mut self) { self.capture.stop(); }
+}