rust tokio: calling async function from sync closure

I have the following problem: I'm trying to call sync closure from async function, but sync closure has to later call another async function.

I cannot make async closure, because they are unstable at the moment: error[E0658]: async closures are unstable

so I have to do it this way somehow.

I found a couple of questions related to the problem, such as this, but when I tried to implement it, im receiving the following error:

Cannot start a runtime from within a runtime.   This happens because a function (like `block_on`)   attempted to block the current thread while the   thread is being used to drive asynchronous tasks.'  

here is playground link which hopefully can show what I'm having problem with.

I'm using tokio as stated in the title.

https://stackoverflow.com/questions/65837485/rust-tokio-calling-async-function-from-sync-closure January 22, 2021 at 07:55AM