Returning a Vector from GroupElement::to_bytes is slow

[JayPavlina]

Creating a vector every time GroupElement::to_bytes() is called is slow because it's allocated on the heap. It would be much faster to return a constant sized array. If the two implementations of GroupElement need to return different sized arrays, an alternative solution is to have to_bytes write to a slice that is passed in.

[lovesh]

You are correct. I don't want to break existing usages of to_bytes by dependent codebases but I can certainly add a new method to_bytearray that takes a mutable slice as you mentioned. And overtime, to_bytes can be removed.

[JayPavlina]

In Rust conventions, naming a function to_ means you are returning something, so I would maybe name the new function write_to_bytes to make it more clear.

Afterwards the new function should be used internally wherever the old one was used.

[lovesh]

Does this sound ok #7

[JayPavlina]

Yes it looks good