title: Two ActiveMQ Durable Subscribers listening to the same topic - Skipped messages by either every now and then
body: <p>Had a quick question regarding subscriber usage in ActiveMQ 5.15.3 using Apache.NSM.ActiveMQ libs for .NET. Looking at two different durable subscribers listening to the same topics that publish XML data, they more or less get and process all the same messages between the two which is expected behavior on this particular case. But occasionally when looking at internal logs one consumer doesn't process one of the messages while the other consumer does and vice versa.</p>
  <p>Of note, both of them are using FailoverTransport connections through TCP.</p>
  <p>We initially thought it to be a bug in the code of one the consumers, but we see that behavior on both of them so I'm more inclined to believe this to be a configuration error. Also, there are no visible ERROR logs or dropped connectivity.</p>
  <p>Could there be a prefetch or timeout problem here? Since I see no obvious errors (messages still get processed fine for the most part on both of them) I could use some pointers or material to scour through on what could be causing this particular behavior.</p>
  <p>I tried looking at internal logs for my internal application, and I also tried debugging this internally through a small console app to no real avail, since the functionality worked as expected on a small sample size.</p>
  <p>I expected that both subscribers will always process the same amount of messages.</p>
  <p>Most of the messages get consumed correctly, but at seemingly random either subscriber will miss/skip a message.</p>