Initialize networking before running connect()

This commit adds a setup_networking function. On most platforms it does
nothing. However, on Windows it calls `wsa_startup`. This ensures that
all networking is set up before anything else is called.

Closes #182

Signed-off-by: John Nunley <dev@notgull.net>

src/lib.rs

@@ -2069,6 +2069,8 @@ fn connect(
     #[cfg(windows)]
     use rustix::fd::AsFd;
 
+    setup_networking();
+
     #[cfg(any(
         target_os = "android",
         target_os = "dragonfly",
@@ -2168,6 +2170,20 @@ fn connect(
     Ok(socket)
 }
 
+#[inline]
+fn setup_networking() {
+    #[cfg(windows)]
+    {
+        // On Windows, we need to call WSAStartup before calling any networking code.
+        // Make sure to call it at least once.
+        static INIT: std::sync::Once = std::sync::Once::new();
+
+        INIT.call_once(|| {
+            let _ = rustix::net::wsa_startup();
+        });
+    }
+}
+
 #[inline]
 fn set_nonblocking(
     #[cfg(unix)] fd: BorrowedFd<'_>,