Struct RingBufferSubscriber 

pub struct RingBufferSubscriber { /* private fields */ }

Retains the last capacity trace events in a circular buffer.

Used for time-travel debugging — the dev tools can read the buffer to replay the sequence of events leading up to the current state or a crash.

Default capacity: 1000 events.

Implementations

impl RingBufferSubscriber

pub fn new(capacity: usize) -> Self

Creates a new ring buffer with the given capacity.

pub fn filtered( capacity: usize, filter: impl Fn(&RosaceTrace) -> bool + Send + Sync + 'static, ) -> Self

A ring buffer that only records events passing filter — the basis of the always-on flight recorder, which excludes high-frequency events so it never becomes a per-frame firehose (D123/O1).

pub fn len(&self) -> usize

Returns the number of events currently held in the buffer.

pub fn is_empty(&self) -> bool

Returns true if the buffer contains no events.

pub fn drain(&self) -> Vec<RosaceTrace>

Drains all buffered events into a Vec, oldest first.

pub fn snapshot(&self) -> Vec<RosaceTrace>

Returns a snapshot of all buffered events, oldest first, without clearing.

pub fn snapshot_timestamped(&self) -> Vec<(Instant, RosaceTrace)>

Like Self::snapshot, but pairs each event with the Instant it was recorded at (D123/O1 — the Perfetto/Chrome trace JSON export needs a timestamp per event; the events themselves mostly don’t carry one).

pub fn export_perfetto_json(&self) -> String

Export the current buffer as a Chrome/Perfetto-loadable trace JSON (Trace Event Format) — drop it in Perfetto UI’s “Open trace file” for a full flamegraph, for free (D123/O1).

Trait Implementations

impl TraceSubscriber for RingBufferSubscriber

fn on_trace(&self, event: &RosaceTrace)

Called for every emitted RosaceTrace event.