Struct CacheChange 

pub struct CacheChange {
    pub sequence_number: SequenceNumber,
    pub payload: Arc<[u8]>,
    pub kind: ChangeKind,
    pub key_hash: Option<[u8; 16]>,
    pub source_timestamp: Option<HeTimestamp>,
}

Single cache entry.

payload is held as Arc<[u8]> — the cache, the writer build- datagram path and reader delivery share a single allocation. This saves the n-fold Vec::clone() per reader proxy in the reliable-writer tick (perf audit F7/F8/F10, ~30-50 % throughput gain for large payloads).

Fields

sequence_number: SequenceNumber

Sequence number (writer-locally unique).

payload: Arc<[u8]>

Payload (serialized sample), reference-counted.

kind: ChangeKind

Kind of the event.

key_hash: Option<[u8; 16]>

Optional PID_KEY_HASH from the inline QoS (Spec §9.6.4.8). Reader side: filled for keyed topics + ALIVE samples with an inline hash or for lifecycle markers (Disposed/Unregistered) by the reader path. Writer side: set by the writer when the path propagates the hash along the sample pipeline.

source_timestamp: Option<HeTimestamp>

Source timestamp of the write (DDSI-RTPS §8.3.7.9 / §8.7.3). When set, the writer prepends an INFO_TS submessage before the DATA so a remote reader can populate SampleInfo.source_timestamp and apply DESTINATION_ORDER = BY_SOURCE_TIMESTAMP. None ⇒ no INFO_TS (the reader falls back to reception order). Held on the change so retransmits carry the original timestamp, not the resend wall-clock.

Implementations

impl CacheChange

pub fn alive(sn: SequenceNumber, payload: Vec<u8>) -> Self

Creates an alive change. Takes Vec<u8> and converts once into Arc<[u8]>. For call sites that already have the allocation as an Arc, there is Self::alive_arc.

pub fn with_source_timestamp(self, ts: Option<HeTimestamp>) -> Self

Attaches a source timestamp (builder style). The writer emits an INFO_TS submessage before the DATA for any change that carries one.

pub fn lifecycle(sn: SequenceNumber, payload: Vec<u8>, kind: ChangeKind) -> Self

Creates a lifecycle marker (Spec §8.2.1.2). payload is the key-only serialization of the disposed/unregistered instance — exactly what lands as PID_KEY_HASH in the inline QoS.

Trait Implementations

impl Clone for CacheChange

fn clone(&self) -> CacheChange

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for CacheChange

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for CacheChange

impl PartialEq for CacheChange

fn eq(&self, other: &CacheChange) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for CacheChange