Struct StreamSegment 

pub struct StreamSegment { /* private fields */ }

Builder for streaming segment metadata.

Manages session/segment IDs and auto-incrementing sequence numbers for real-time streaming patterns (voice, video, sensor streams).

The state transitions are easy to get subtly wrong, so they are worth spelling out: chunk stamps the current (segment_id, seq) and then auto-increments seq; next_segment bumps segment_id and resets seq to 0; and flush advances to a new segment and emits a chunk marked flush = true, fin = false (the prior segment is discarded, not completed, so it intentionally never gets a fin = true).

Example

use dora_node_api::{
    StreamSegment,
    metadata::{FIN, FLUSH, SEGMENT_ID, SEQ, get_bool_param, get_integer_param},
};

let mut seg = StreamSegment::with_session_id("session-1".to_string());

// `chunk` stamps the current (segment, seq), then advances seq.
let first = seg.chunk(false);
assert_eq!(get_integer_param(&first, SEGMENT_ID), Some(0));
assert_eq!(get_integer_param(&first, SEQ), Some(0));
assert_eq!(get_bool_param(&first, FIN), Some(false));

let second = seg.chunk(true); // mark this chunk as the end of the segment
assert_eq!(get_integer_param(&second, SEQ), Some(1)); // seq auto-incremented
assert_eq!(get_bool_param(&second, FIN), Some(true));

// `flush` starts a new segment (seq reset to 0) and marks flush=true,
// fin=false: the old queued data is discarded, not completed.
let flushed = seg.flush();
assert_eq!(get_integer_param(&flushed, SEGMENT_ID), Some(1));
assert_eq!(get_integer_param(&flushed, SEQ), Some(0));
assert_eq!(get_bool_param(&flushed, FLUSH), Some(true));
assert_eq!(get_bool_param(&flushed, FIN), Some(false));

Implementations

impl StreamSegment

pub fn new() -> Self

Start a new session with a generated session ID and segment 0.

pub fn with_session_id(session_id: String) -> Self

Start a new session with an explicit session ID.

pub fn next_segment(&mut self) -> i64

Advance to a new segment (resets seq to 0). Returns the new segment_id.

pub fn chunk(&mut self, fin: bool) -> MetadataParameters

Build metadata parameters for a chunk. Auto-increments seq.

pub fn flush(&mut self) -> MetadataParameters

Build metadata for a flush message (new segment, discards older queued data).

Advances to a new segment, then emits a chunk with flush=true and fin=false. The prior segment ends without a fin=true signal – this is intentional for interruption semantics (the old data is being discarded, not completed).

Note: flush discards all queued messages on the receiver’s input regardless of session_id. Do not multiplex independent sessions on a single DataId when using flush.

pub fn session_id(&self) -> &str

Returns the session ID.

pub fn segment_id(&self) -> i64

Returns the current segment ID.

pub fn seq(&self) -> i64

Returns the sequence number that will be used by the next chunk() call.

Trait Implementations

impl Default for StreamSegment

fn default() -> Self

Returns the “default value” for a type.