The bindings have exported `io::Error` as, basically,
`io::ErrorKind`, for quite some time, so there's little reason to
not just export `io::ErrorKind` as well.
/// A length descriptor in the packet didn't describe the later data correctly
BadLengthDescriptor,
/// Error from std::io
- Io(/// (C-not exported) as ErrorKind doesn't have a reasonable mapping
- io::ErrorKind),
+ Io(io::ErrorKind),
/// The message included zlib-compressed values, which we don't support.
UnsupportedCompression,
}