Add a FIXME about the bogosity of aio::ip_to_sbuf

src/lib/aio.rs

@@ -45,6 +45,9 @@ tag request {
 type ctx = chan<request>;
 
 fn ip_to_sbuf(ip: net::ip_addr) -> *u8 {
+    // FIXME: This is broken. We're creating a vector, getting a pointer
+    // to its buffer, then dropping the vector. On top of that, the vector
+    // created by istr::bytes is not null-terminated.
     vec::to_ptr(istr::bytes(net::format_addr(ip)))
 }