Replace AioCb::from_bytes with more generic from_boxed_slice

Supporting the bytes crate was unnecessarily specific.  This change
replaces from_bytes and from_bytes_mut with from_boxed_slice and
from_boxed_mut_slice, which can work with anything that implements
Borrow<[u8]> and BorrowMut<[u8]>, respectively.

CHANGELOG.md

@@ -6,6 +6,8 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 ## [Unreleased]
 
 ### Added
+- Added safe support for nearly any buffer type in the `sys::aio` module.
+  ([#872](https://github.com/nix-rust/nix/pull/872))
 - Added `sys::aio::LioCb` as a wrapper for `libc::lio_listio`.
   ([#872](https://github.com/nix-rust/nix/pull/872))
 - Added `getsid` in `::nix::unistd`
@@ -31,6 +33,9 @@ This project adheres to [Semantic Versioning](http://semver.org/).
   ([#837](https://github.com/nix-rust/nix/pull/837))
 
 ### Removed
+- Removed explicit support for the `bytes` crate from the `sys::aio` module.
+  See `sys::aio::AioCb::from_boxed_slice`s examples for alternatives.
+  ([#872](https://github.com/nix-rust/nix/pull/872))
 - Removed `sys::aio::lio_listio`.  Use `sys::aio::LioCb::listio` instead.
   ([#872](https://github.com/nix-rust/nix/pull/872))
 

Cargo.toml

@@ -17,15 +17,13 @@ bitflags = "1.0"
 cfg-if = "0.1.0"
 void = "1.0.2"
 
-[dependencies.bytes]
-version = "0.4.5"
-# Don't include the optional serde feature
-default-features = false
-
 [target.'cfg(target_os = "dragonfly")'.build-dependencies]
 gcc = "0.3"
 
 [dev-dependencies]
+# The examples use on a new feature of Bytes which should be available in 0.5.0
+# https://github.com/carllerche/bytes/pull/185
+bytes = { git = "https://github.com/asomers/bytes", rev = "b57934d" }
 lazy_static = "1"
 rand = "0.4"
 tempdir = "0.3"

src/lib.rs

@@ -16,7 +16,6 @@
 #![deny(missing_debug_implementations)]
 
 // External crates
-extern crate bytes;
 #[macro_use]
 extern crate bitflags;
 #[macro_use]