B4R Tutorial Large strings joinstring & astream

I need to create a large string for http call. Using joinStrings if string variable is more than ~ 100 characters it crashes. I saw that an alternative is to use astream but how am i going to store the http url in a variable as is must be build using several globalstore variables that must be combiled.
If i use a large byte variable how can i cancatenate byte fields.

 

[Erel]

Assuming that you must create a single large string then you should increase #StackBufferSize.