`async_scope::spawn` cost a lot in ref counting and heap alloc, how to optimize?

Hi everyone, I'm using `async_scope::spawn` in a very hot code path. And I find it's very slow due to the reference counting and heap allocation.

the senders I'm spawning have different scheduelrs(unique scheudler per sender). So `ex::bulk` doesn't apply here.

I wonder is there any way to optimize or workaround?

can anyone help me? thanks in advance!