mercurial/cext/base85.pyi

rust: Make NodePrefix allocation-free and Copy, remove NodePrefixRef

The `*Ref` struct only existed to avoid allocating `Vec`s
when cloning `NodePrefix`, but we can avoid having `Vec`
in the first place by using an inline array instead.

This makes `NodePrefix` 21 bytes (with 1 for the length)
which is smaller than before as `Vec` alone is 24 bytes.

Differential Revision: https://phab.mercurial-scm.org/D9863

from typing import Optional

version: int

def b85encode(text: bytes, pad: Optional[int]) -> bytes: ...
def b85decode(text: bytes) -> bytes: ...