mysql::Conn has inconsistent implementations of Sync on Windows and macOS

[shepmaster]

This code compiles fine on macOS, but fails on Windows:

#[macro_use]
extern crate lazy_static;
extern crate mysql;

use mysql::*;

fn some_fn() {
    lazy_static! {
        static ref CONNECTION: Conn = Conn::new("mysql://root:password@127.0.0.1:3306/mydb?prefer_socket=false").unwrap();
    }
}

fn main() {}

[dependencies]
lazy_static = "1.0.0"
mysql = "12.2.0"

error[E0277]: the trait bound `*mut std::os::raw::c_void: std::marker::Sync` is not satisfied in `winapi::minwinbase::OVERLAPPED`
  --> src\main.rs:8:5
   |
8  | /     lazy_static! {
9  | |         static ref CONNECTION: Conn = Conn::new("mysql://root:password@127.0.0.1:3306/mydb?prefer_socket=false").unwrap();
10 | |     }
   | |_____^ `*mut std::os::raw::c_void` cannot be shared between threads safely
   |
   = help: within `winapi::minwinbase::OVERLAPPED`, the trait `std::marker::Sync` is not implemented for `*mut std::os::raw::c_void`
   = note: required because it appears within the type `winapi::minwinbase::OVERLAPPED`
   = note: required because of the requirements on the impl of `std::marker::Sync` for `std::ptr::Unique<winapi::minwinbase::OVERLAPPED>`
   = note: required because it appears within the type `std::boxed::Box<winapi::minwinbase::OVERLAPPED>`
   = note: required because it appears within the type `named_pipe::Overlapped`
   = note: required because it appears within the type `named_pipe::PipeClient`
   = note: required because it appears within the type `std::option::Option<named_pipe::PipeClient>`
   = note: required because it appears within the type `std::io::BufWriter<named_pipe::PipeClient>`
   = note: required because it appears within the type `std::option::Option<std::io::BufWriter<named_pipe::PipeClient>>`
   = note: required because it appears within the type `bufstream::InternalBufWriter<named_pipe::PipeClient>`
   = note: required because it appears within the type `std::io::BufReader<bufstream::InternalBufWriter<named_pipe::PipeClient>>`
   = note: required because it appears within the type `bufstream::BufStream<named_pipe::PipeClient>`
   = note: required because it appears within the type `mysql::io::Stream`
   = note: required because it appears within the type `std::option::Option<mysql::io::Stream>`
   = note: required because it appears within the type `mysql::Conn`
   = note: required by `lazy_static::lazy::Lazy`
   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)

[blackbeam]

Thanks for report.

It's fine for OVERLAPPED to be Sync and Send but traits was not automatically implemented because of a c_void.

Fix published in v12.3.0.