Struct ParkWriter 

pub struct ParkWriter { /* private fields */ }

Writes emitted parks to disk. A replace park (a stronger close pair — same layer) reuses the previous index and overwrites, so the timelapse keeps exactly one frame per park; latest_park.jpg is updated atomically (temp + rename) so a polling dashboard never reads a half-written file.

Implementations

impl ParkWriter

pub fn new(out_dir: PathBuf) -> Self

pub fn emitted(&self) -> u64

Number of distinct park frames written so far (a replace doesn’t increment it).

pub fn write(&mut self, park: &Park, ring_jpeg: &Path) -> Result<ParkWritten>

Copy ring_jpeg to latest_park.jpg (atomic) and park_NNNNNN.jpg, and append a line to parks.jsonl. Returns the index written and whether it REPLACED the previous park (a stronger close pair, same layer — overwritten, not a new frame).