complete method
Permanently removes a message from the _queue. This method is usually used to remove the message after successful processing. Parameters:
message
a message to remove. Return Future that recive a null if all done Throws error
Implementation
@override
Future complete(MessageEnvelope message) async {
_checkOpened('');
amqp.AmqpMessage envelope = message.getReference();
if (envelope != null) {
envelope.ack();
message.setReference(null);
logger.trace(message.correlation_id, 'Completed message %s at %s',
[message, name]);
}
}