Vendor dependencies

Let's see how I like this workflow.

vendor/tokio/tests/process_issue_2174.rs

@@ -0,0 +1,45 @@
+#![cfg(feature = "process")]
+#![warn(rust_2018_idioms)]
+// This test reveals a difference in behavior of kqueue on FreeBSD. When the
+// reader disconnects, there does not seem to be an `EVFILT_WRITE` filter that
+// is returned.
+//
+// It is expected that `EVFILT_WRITE` would be returned with either the
+// `EV_EOF` or `EV_ERROR` flag set. If either flag is set a write would be
+// attempted, but that does not seem to occur.
+#![cfg(all(unix, not(target_os = "freebsd")))]
+
+use std::process::Stdio;
+use std::time::Duration;
+use tokio::io::AsyncWriteExt;
+use tokio::process::Command;
+use tokio::time;
+use tokio_test::assert_err;
+
+#[tokio::test]
+async fn issue_2174() {
+    let mut child = Command::new("sleep")
+        .arg("2")
+        .stdin(Stdio::piped())
+        .stdout(Stdio::null())
+        .spawn()
+        .unwrap();
+    let mut input = child.stdin.take().unwrap();
+
+    // Writes will buffer up to 65_636. This *should* loop at least 8 times
+    // and then register interest.
+    let handle = tokio::spawn(async move {
+        let data = [0u8; 8192];
+        loop {
+            input.write_all(&data).await.unwrap();
+        }
+    });
+
+    // Sleep enough time so that the child process's stdin's buffer fills.
+    time::sleep(Duration::from_secs(1)).await;
+
+    // Kill the child process.
+    child.kill().await.unwrap();
+
+    assert_err!(handle.await);
+}