Vendor dependencies

Let's see how I like this workflow.

vendor/tokio/tests/signal_drop_rt.rs

@@ -0,0 +1,44 @@
+#![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
+#![cfg(unix)]
+
+mod support {
+    pub mod signal;
+}
+use support::signal::send_signal;
+
+use tokio::runtime::Runtime;
+use tokio::signal::unix::{signal, SignalKind};
+
+#[test]
+fn dropping_loops_does_not_cause_starvation() {
+    let kind = SignalKind::user_defined1();
+
+    let first_rt = rt();
+    let mut first_signal =
+        first_rt.block_on(async { signal(kind).expect("failed to register first signal") });
+
+    let second_rt = rt();
+    let mut second_signal =
+        second_rt.block_on(async { signal(kind).expect("failed to register second signal") });
+
+    send_signal(libc::SIGUSR1);
+
+    first_rt
+        .block_on(first_signal.recv())
+        .expect("failed to await first signal");
+
+    drop(first_rt);
+    drop(first_signal);
+
+    send_signal(libc::SIGUSR1);
+
+    second_rt.block_on(second_signal.recv());
+}
+
+fn rt() -> Runtime {
+    tokio::runtime::Builder::new_current_thread()
+        .enable_all()
+        .build()
+        .unwrap()
+}