Function pulsar_sys::pulsar_consumer_configuration_set_message_listener

pub unsafe extern "C" fn pulsar_consumer_configuration_set_message_listener(
    consumer_configuration: *mut pulsar_consumer_configuration_t, 
    messageListener: pulsar_message_listener, 
    ctx: *mut c_void
)

A message listener enables your application to configure how to process and acknowledge messages delivered. A listener will be called in order for every message received.