There have only been two PRs merged that touched the `io` crate since it
as last released. The changes are additive so we can do a pre-0.1 point
release.
In preparation for release bump the version and add a changelog entry.
We attempted to release with the current 0.1.0 version forgetting that
we had previously released an empty crate with that version to reserve
the name on crates.io.
Bump the version to 0.1.1 and release the actual code.
In order to support standard (de)serialization of structs, the
`rust-bitcoin` ecosystem uses the standard `std::io::{Read,Write}`
traits. This works great for environments with `std`, however sadly
the `std::io` module has not yet been added to the `core` crate.
Thus, in `no-std`, the `rust-bitcoin` ecosystem has historically
used the `core2` crate to provide copies of the `std::io` module
without any major dependencies. Sadly, its one dependency,
`memchr`, recently broke our MSRV.
Worse, because we didn't want to take on any excess dependencies
for `std` builds, `rust-bitcoin` has had to have
mutually-exclusive `std` and `no-std` builds. This breaks general
assumptions about how features work in Rust, causing substantial
pain for applications far downstream of `rust-bitcoin` crates.
Here, we add a new `bitcoin_io` crate, making it an unconditional
dependency and using its `io` module in the in-repository crates
in place of `std::io` and `core2::io`. As it is not substantial
additional code, the `hashes` io implementations are no longer
feature-gated.
This doesn't actually accomplish anything on its own, only adding
the new crate which still depends on `core2`.
Tobin C. Harding
Matt Corallo