Deprecate unsafe pin projection macros #29
Description
As said in #26, I would like to deprecate unsafe pin projection macros in the future as there are already safe alternatives (pin-project, pin-project-lite).
However, futures and other crates still depend on it, I don't have a clear opinion as to when to do this yet.
UPDATE: use of these macros in futures-rs has been removed (rust-lang/futures-rs#2128, rust-lang/futures-rs#2148)