Issue w Interop Code uses Asynchronous Call(BeginInvoke and EndInv

[H Wu]

I have an application in VB6 (Single Thread Apartment) reference an Interop
code (register as COM written in C# that use Asynchronous Call) that help
process calls back and forward with VB6 app and another C# code dll. The
issue is when memory is at the max we see our application begin to hang for
one or two minutes before it come back (or actually Visio will hang which we
use as GUI interface). I try to used DoEvents to pump up our application but
still see the hang issue happen. I believe the issue may fall in our VB6 code
since it Single Thread but is there a way around this without having to
convert VB6 code to NET(VB.Net or C#)