What does the initial buffer size in Variable Transport Delay block alters?

I'm working with a model that needs a variable transport delay block. I tried setting the "Initial buffer size" parameter to the default 1024. But when I run the simulation, I get the yellow warning that the buffer size was too small and it was increased to 10240 and that I should consider permanently increasing this buffer size in order to generate C/C++ code from the model.

I've tried to generate the code with the parameter set to 1024 and it worked. So, I'm wondering now what does the initial buffer size parameter changes in the Variable Transport Delay block.

[shweta]

Can you tell me, how did you do this ,i am also facing the same problem