Vendor dependencies

Let's see how I like this workflow.

vendor/bytes/tests/test_take.rs

@@ -0,0 +1,32 @@
+#![warn(rust_2018_idioms)]
+
+use bytes::buf::Buf;
+use bytes::Bytes;
+
+#[test]
+fn long_take() {
+    // Tests that get a take with a size greater than the buffer length will not
+    // overrun the buffer. Regression test for #138.
+    let buf = b"hello world".take(100);
+    assert_eq!(11, buf.remaining());
+    assert_eq!(b"hello world", buf.chunk());
+}
+
+#[test]
+fn take_copy_to_bytes() {
+    let mut abcd = Bytes::copy_from_slice(b"abcd");
+    let abcd_ptr = abcd.as_ptr();
+    let mut take = (&mut abcd).take(2);
+    let a = take.copy_to_bytes(1);
+    assert_eq!(Bytes::copy_from_slice(b"a"), a);
+    // assert `to_bytes` did not allocate
+    assert_eq!(abcd_ptr, a.as_ptr());
+    assert_eq!(Bytes::copy_from_slice(b"bcd"), abcd);
+}
+
+#[test]
+#[should_panic]
+fn take_copy_to_bytes_panics() {
+    let abcd = Bytes::copy_from_slice(b"abcd");
+    abcd.take(2).copy_to_bytes(3);
+}