@salmon-summer-38098 my newbie approach is to place an

assert!(false)

and check the stacktrace, like this

stack backtrace:
   1:        0x1126812ca - std::sys::imp::backtrace::tracing::imp::write::hd3b65cdfe843284c
   2:        0x11268d94f - std::panicking::default_hook::{{closure}}::hf2b7428652613d83
   3:        0x11268d5f7 - std::panicking::default_hook::h5da8f27db5582938
   4:        0x11268de16 - std::panicking::rust_panic_with_hook::hcef1e67c646c6802
   5:        0x11250cda4 - std::panicking::begin_panic::h2e3c614d072c01a4
   6:        0x112557bda - engine::graph::InnerGraph::ensure_entry::h8365ab4ff57947ef
   7:        0x112558bff - engine::nodes::Context::get::h80475337cafa26de
   8:        0x112561bdb - <engine::nodes::Task as engine::nodes::Node>::run::h701a08988642e51c
   9:        0x11256352d - <engine::nodes::NodeKey as engine::nodes::Node>::run::h511f2ed6601a7e25
  10:        0x11250f023 - std::panicking::try::do_call::h7c43891a18ad8eb7
  11:        0x1126903ca - __rust_maybe_catch_panic
  12:        0x1125053dd - <futures_cpupool::MySender<F, core::result::Result<<F as futures::future::Future>::Item, <F as futures::future::Future>::Error>> as futures::future::Future>::poll::h02a6232dedfe526f
  13:        0x112599b98 - futures::task_impl::Run::run::h2e8f42ba304d5602
  14:        0x1125952fa - std::panicking::try::do_call::h5d76dda7fccc29e1
  15:        0x1126903ca - __rust_maybe_catch_panic