Add cause of cancel cancelation token

[rekby]

Is your feature request related to a problem? Please describe.
Log reason of token cancelation - it helps with debug process.

Describe the solution you'd like
I want add functions to struct CancellationToken

fun cancel_with_cause<T: Into<CancelationCause>>(cause: T) {}
fun cancel_cause()->Option<CancelCause> {}

with causes

#[non_exhaustive]
enum CancelationCause{
    Empty, // used for cancel with cancel() func - without specified cause
    Str(&'static str),
    String(String),
    Err(Box<std::error::Error + Send + Sync>),
    Debug(Box<std::fmt::Debug + Send + Sync>),
    Any(std::any::Any)
}

cancel_with_cause - allow set cause of cancelation
cancel_cause - check if token cancelled and reason of it.

Describe alternatives you've considered

• create trait, with default implementation for CancellationToken (will need box for usage as trait)
• create other type for cancel with reason (split code for incompatible parts: with and without support reason).

Additional context
Similar functional will add in standard lib of go1.20:
golang/go#51365
golang/go@5b42f89