Struct Cursor 

pub struct Cursor { /* private fields */ }

A resumable reader over one topic. Build it with Topic::replay. Owns a cheap Laser clone, so it moves into a tokio::spawn or is stored beside the Laser rather than borrowing it.

Implementations

impl Cursor

pub fn from_offsets(self, offsets: Vec<u64>) -> Self

Resume from previously persisted per-partition offsets: the next offset to read on each partition, exactly what an earlier offsets returned. A shorter vec than the topic’s partition count is padded with 0 (read those partitions from the start).

pub fn batch(self, batch: u32) -> Self

Size each server poll at batch messages per partition (default 1000).

This is the per-request size, not a ceiling on one poll: a poll keeps requesting until it reaches the partition’s tail or the per-partition drain ceiling, whichever comes first. Persist offsets and poll again to continue past the ceiling.

pub fn offsets(&self) -> &[u64]

The next offset to read on each partition. Persist this to resume later with from_offsets.

pub fn stream(self) -> impl Stream<Item = Result<Message, LaserError>>

This cursor as a Stream of messages, one at a time, draining everything currently appended and ending (like the async reader in the Python binding) once caught up. A later stream() on a fresh cursor seeded from the persisted offsets resumes from there. Use it with futures::StreamExt: while let Some(message) = stream.next().await. The bounded-read primitive as a stream, not a substitute for the reliable consumer’s continuous delivery.

pub async fn poll(&mut self) -> Result<Vec<Message>, LaserError>

Drain everything appended since the last poll, advancing the cursor. Returns the new messages ordered by Iggy timestamp (then partition, offset), or an empty vec when the reader is caught up (or the topic does not exist yet).