Function pulsar_sys::pulsar_consumer_unsubscribe_async

pub unsafe extern "C" fn pulsar_consumer_unsubscribe_async(
    consumer: *mut pulsar_consumer_t, 
    callback: pulsar_result_callback, 
    ctx: *mut c_void
)

Asynchronously unsubscribe the current consumer from the topic.

This method will block until the operation is completed. Once the consumer is unsubscribed, no more messages will be received and subsequent new messages will not be retained for this consumer.

This consumer object cannot be reused.

@param callback the callback to get notified when the operation is complete