Struct Recorder 

pub struct Recorder { /* private fields */ }

Append-only recorder. Writes the session header once, then one JSONL line per Msg the main loop feeds the reducer.

Implementations

impl Recorder

pub fn open(path: impl Into<PathBuf>) -> Result<Self>

Open path for append. Creates the file if it doesn’t exist.

pub fn record_header(&mut self, header: &SessionHeader) -> Result<()>

Write the session header. Called once, before the first record_msg, and flushed immediately — a replay of a crashed session should still find a parseable header.

pub fn record_msg(&mut self, now: DateTime<Local>, msg: &Msg) -> Result<()>

Record one reducer input. now must be the same value the driver stamps into state.now for this tick — that identity is what makes the recorded ts a faithful replay clock.

Msg::Tick is deliberately NOT recorded: the reducer’s Tick arm is a documented no-op (render derives the spinner from state.now), so a 60 Hz tick stream would bloat the log by megabytes per hour for zero replay fidelity. The tick_is_a_reducer_noop invariant test pins this — if Tick ever grows state effects, that test fails and ticks must be recorded again. Old logs containing Tick entries still fold fine (a no-op replays as a no-op).

pub fn record_trailer( &mut self, now: DateTime<Local>, session: &Session, ) -> Result<()>

Seal the recording with a fingerprint of the final session state, so a future --replay can verify its fold reproduces what this live session actually saw (not merely that the fold is self-consistent). Written on clean exit; a crashed session simply has no trailer.

pub fn flush(&mut self) -> Result<()>

Trait Implementations

impl Drop for Recorder

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.