Struct Sink 

pub struct Sink<T: Record> { /* private fields */ }

A streaming data sink.

Sinks receive records from a Source and distribute them to subscribers. The sink supports both single-subscriber and broadcast modes.

Subscription Model

When you call subscribe(), you get a Subscription that receives records from this sink. If you subscribe multiple times, the sink automatically enters broadcast mode where each subscriber gets a copy of every record.

Performance Notes

• Single subscriber mode: Zero overhead, direct channel access
• Broadcast mode: Uses RwLock for subscriber list (read-heavy optimization)
• poll_and_distribute(): Takes a read lock (fast, non-blocking with other readers)
• subscribe(): Takes a write lock (rare, happens at setup time)

Example

let (source, sink) = streaming::create::<MyEvent>(1024);

// Subscribe to receive records
let subscription = sink.subscribe();

// Process records
while let Some(batch) = subscription.poll() {
    process(batch);
}

Implementations

impl<T: Record> Sink<T>

pub fn subscribe(&self) -> Subscription<T>

Creates a subscription to receive records from this sink.

The first subscriber receives records directly from the source channel. Additional subscribers trigger broadcast mode where records are copied.

Returns

A Subscription that can be used to poll or receive records.

Performance

This method takes a write lock and should only be called during setup, not on the hot path. Subscription setup is O(1).

Panics

Panics if the internal lock is poisoned (should not happen in normal use).

pub fn subscriber_count(&self) -> usize

Returns the number of active subscribers.

pub fn mode(&self) -> SinkMode

Returns the sink mode based on subscriber count.

pub fn schema(&self) -> SchemaRef

Returns the schema for this sink.

pub fn is_disconnected(&self) -> bool

Returns true if the source has been dropped.

pub fn pending(&self) -> usize

Returns the number of pending items from the source.

pub fn poll_and_distribute(&self) -> usize

where T: Clone,

Polls for records and distributes them to subscribers.

In single-subscriber mode, this is a no-op (direct channel). In broadcast mode, this copies records to all subscriber channels.

Returns the number of records distributed.

Performance

Snapshots subscriber producers under the read lock (cheap Arc bumps), then releases the lock before the poll loop to avoid holding it during I/O.

Trait Implementations

impl<T: Record + Debug> Debug for Sink<T>

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

Formats the value using the given formatter.