private async ValueTask <IMessage <T> > FetchSingleMessageFromBroker()
{
// Just being cautious
if (IncomingMessages.Count > 0)
{
_log.Error("The incoming message queue should never be greater than 0 when Queue size is 0");
IncomingMessages.Empty();
}
IMessage <T> message;
try
{
// if cnx is null or if the connection breaks the connectionOpened function will send the flow again
_waitingOnReceiveForZeroQueueSize = true;
if (Connected())
{
IncreaseAvailablePermits(_clientCnx);
}
do
{
message = await IncomingMessages.ReceiveAsync();
_lastDequeuedMessageId = message.MessageId;
var msgCnx = ((Message <T>)message).Cnx();
// synchronized need to prevent race between connectionOpened and the check "msgCnx == cnx()"
// if message received due to an old flow - discard it and wait for the message from the
// latest flow command
if (msgCnx == _clientCnx)
{
_waitingOnReceiveForZeroQueueSize = false;
break;
}
} while(true);
Stats.UpdateNumMsgsReceived(message);
return(message);
}
catch (Exception e)
{
Stats.IncrementNumReceiveFailed();
throw PulsarClientException.Unwrap(e);
}
finally
{
// Finally blocked is invoked in case the block on incomingMessages is interrupted
_waitingOnReceiveForZeroQueueSize = false;
// Clearing the queue in case there was a race with messageReceived
IncomingMessages.Empty();
}
}
public Task <Message> ReceiveMessageAsync(CancellationToken cancellationToken)
{
return(IncomingMessages.ReceiveAsync(cancellationToken));
}