Callback handler woes

Hi,
I am using the C# wrapper for my usbuirt and have found an odd behavior, I am curious if this is a "undocumented feature." What I have found is that while the registered callback method is executing, no ir codes can be transmitted. If I wait and transmit the same code AFTER the receive callback has finished, the code is transmitted fine. I have tested with the blocking and non-blocking methods, same result.
Is the hardware device driver capable of sending while a receive event is executing? Has anyone else encountered this with the C# wrapper?
I am using the C# wrapper for my usbuirt and have found an odd behavior, I am curious if this is a "undocumented feature." What I have found is that while the registered callback method is executing, no ir codes can be transmitted. If I wait and transmit the same code AFTER the receive callback has finished, the code is transmitted fine. I have tested with the blocking and non-blocking methods, same result.
Is the hardware device driver capable of sending while a receive event is executing? Has anyone else encountered this with the C# wrapper?