Vendor dependencies

Let's see how I like this workflow.

vendor/tokio/tests/unwindsafe.rs

@@ -0,0 +1,42 @@
+#![warn(rust_2018_idioms)]
+#![cfg(all(feature = "full", not(tokio_wasi)))] // Wasi does not support panic recovery
+
+use std::panic::{RefUnwindSafe, UnwindSafe};
+
+#[test]
+fn notify_is_unwind_safe() {
+    is_unwind_safe::<tokio::sync::Notify>();
+}
+
+#[test]
+fn join_handle_is_unwind_safe() {
+    is_unwind_safe::<tokio::task::JoinHandle<()>>();
+}
+
+#[test]
+fn net_types_are_unwind_safe() {
+    is_unwind_safe::<tokio::net::TcpListener>();
+    is_unwind_safe::<tokio::net::TcpSocket>();
+    is_unwind_safe::<tokio::net::TcpStream>();
+    is_unwind_safe::<tokio::net::UdpSocket>();
+}
+
+#[test]
+#[cfg(unix)]
+fn unix_net_types_are_unwind_safe() {
+    is_unwind_safe::<tokio::net::UnixDatagram>();
+    is_unwind_safe::<tokio::net::UnixListener>();
+    is_unwind_safe::<tokio::net::UnixStream>();
+}
+
+#[test]
+#[cfg(windows)]
+fn windows_net_types_are_unwind_safe() {
+    use tokio::net::windows::named_pipe::NamedPipeClient;
+    use tokio::net::windows::named_pipe::NamedPipeServer;
+
+    is_unwind_safe::<NamedPipeClient>();
+    is_unwind_safe::<NamedPipeServer>();
+}
+
+fn is_unwind_safe<T: UnwindSafe + RefUnwindSafe>() {}