Is there a reason that # or + doesn’t work for binary concatenation? I had an issue over the weekend where I was trying to push content in via the dfx command line. You are limited to about 1MB on the command line. A 400KB image encoded as “\FF\FF…” over runs that. I tried to use Array.append but I eventually hit the cycle limit when my hash map got over a certain point.
It would be great to have a memory efficient append for binary data. It will also be important if you are trying to build up a large file of a certain format that needs to be encoded.