Vendor dependencies

Let's see how I like this workflow.

vendor/tokio/tests/support/leaked_buffers.rs

@@ -0,0 +1,26 @@
+/// Can create buffers of arbitrary lifetime.
+/// Frees created buffers when dropped.
+///
+/// This struct is of course unsafe and the fact that
+/// it must outlive the created slices has to be ensured by
+/// the programmer.
+///
+/// Used at certain test scenarios as a safer version of
+/// Vec::leak, to satisfy the address sanitizer.
+pub struct LeakedBuffers {
+    leaked_vecs: Vec<Box<[u8]>>,
+}
+
+impl LeakedBuffers {
+    pub fn new() -> Self {
+        Self {
+            leaked_vecs: vec![],
+        }
+    }
+    pub unsafe fn create<'a>(&mut self, size: usize) -> &'a mut [u8] {
+        let mut new_mem = vec![0u8; size].into_boxed_slice();
+        let slice = std::slice::from_raw_parts_mut(new_mem.as_mut_ptr(), new_mem.len());
+        self.leaked_vecs.push(new_mem);
+        slice
+    }
+}