Struct KafkaConsumer 

#[non_exhaustive]
pub struct KafkaConsumer;

The public entry point for constructing a Consumer.

Translates org.apache.kafka.clients.consumer.KafkaConsumer, whose public constructors are the only way a Java user obtains a consumer. Java’s class is a thin delegating wrapper: its constructor calls ConsumerDelegateCreator.create(config, keyDeserializer, valueDeserializer) (KafkaConsumer.java:615), which switches on group.protocol and returns either an AsyncKafkaConsumer or a ClassicKafkaConsumer (ConsumerDelegateCreator.java:57-66); its 55 other methods forward verbatim to that delegate.

Rust keeps only the constructor. The delegate is returned directly as Box<dyn Consumer<K, V>> rather than being stored in a wrapper that re-forwards every method, because Consumer is dyn compatible — so the caller holds exactly what Java’s wrapper would have held, and the 55 forwarding bodies carry no behavior to translate. ConsumerDelegate and ConsumerDelegateCreator are out of scope per consumer-threading.md §20 (“collapses to direct Box::new(AsyncKafkaConsumer)”); this type is where that collapsed creator lives.

Implementations

impl KafkaConsumer

pub fn new<K, V>( config: ConsumerConfig, key_deserializer: Box<dyn Deserializer<K>>, value_deserializer: Box<dyn Deserializer<V>>, ) -> Result<Box<dyn Consumer<K, V>>, Error>

where K: Send + Sync + 'static, V: Send + Sync + 'static,

Constructs a new Consumer from a configuration and explicit key/value Deserializers.

For group.protocol=consumer (KIP-848), this returns Box::new(AsyncKafkaConsumer::new(...)?) — the production consumer built end-to-end with SubscriptionState, ConsumerMetadata, NetworkClient, every RequestManager, and a single bg task (ConsumerNetworkThread). For group.protocol=classic, returns Error::unsupported_version per consumer-threading.md §20 (classic protocol deferred to a later milestone).

Java passes deserializers via ConsumerConfig reflection; Rust takes them as explicit Box<dyn> parameters (Phase 1 decision not to translate reflection machinery). The consumer wraps them in Arc<Deserializers<K, V>> internally for sharing with Fetcher/FetchCollector (Shape B).

MockConsumer (Phase 3) does NOT come through this factory — it has its own constructor. The factory is for the production consumer only.