add write from slice function

[cecton]

tbh I would prefer this to stay lazy. Here you're allocating a big memory buffer with the whole stuff. Not it really matters for embedded but you know... maybe some device has huge memory I don't know.

Do you know you can put a slice into a cursor and pass that instead?

[gnxlxnxx]

Do you know you can put a slice into a cursor and pass that instead?

No, didn't know this, changed this to use a Cursor now

[cecton]

feel free to merge