572 join error

[idruzhitskiy]

Closes #572

[ikopylov]

I searched for information about the cancelled error. There are comments in several places where it is indicated that there is a possibility that there will be a cancellation error when the runtime is stopped. Comments are here:

1. Observability of JoinError::Cancelled tokio-rs/tokio#2077 (comment)
2. https://users.rust-lang.org/t/can-this-tokio-task-get-canceled-if-i-await-its-handle/88203/4

So, unfortunately, we should handle cancelled error in a special way