Sub Process_Globals
Public Serial1 As Serial
End Sub
Private Sub AppStart
Serial1.Initialize(115200)
Log("AppStart")
End Sub
It is important to understand that this includes most of the B4R thin layer. It means that it will not increase much as your program grow.
In most cases the size of the external Arduino libraries will be much larger than your code or the B4R libraries code.
The performance of B4R programs is similar to the performance of programs written in C (in many cases it will be better as B4R programs make it simple to use timers and other nice scheduling features: https://www.b4x.com/android/forum/threads/65989/#content).