Vendor dependencies

Let's see how I like this workflow.

vendor/tokio/tests/process_kill_on_drop.rs

@@ -0,0 +1,44 @@
+#![cfg(all(unix, feature = "process"))]
+#![warn(rust_2018_idioms)]
+
+use std::io::ErrorKind;
+use std::process::Stdio;
+use std::time::Duration;
+use tokio::io::AsyncReadExt;
+use tokio::process::Command;
+use tokio::time::sleep;
+use tokio_test::assert_ok;
+
+#[tokio::test]
+async fn kill_on_drop() {
+    let mut cmd = Command::new("bash");
+    cmd.args(&[
+        "-c",
+        "
+       # Fork another child that won't get killed
+       sh -c 'sleep 1; echo child ran' &
+       disown -a
+
+       # Await our death
+       sleep 5
+       echo hello from beyond the grave
+    ",
+    ]);
+
+    let e = cmd.kill_on_drop(true).stdout(Stdio::piped()).spawn();
+    if e.is_err() && e.as_ref().unwrap_err().kind() == ErrorKind::NotFound {
+        println!("bash not available; skipping test");
+        return;
+    }
+    let mut child = e.unwrap();
+
+    sleep(Duration::from_secs(2)).await;
+
+    let mut out = child.stdout.take().unwrap();
+    drop(child);
+
+    let mut msg = String::new();
+    assert_ok!(out.read_to_string(&mut msg).await);
+
+    assert_eq!("child ran\n", msg);
+}