tokio-inherit-task-local 0.2.0

Task local variables for tokio that can be inherited across a spawn
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# tokio-inherit-task-local

Provides functionality very similar to [`tokio::task_local`](https://docs.rs/tokio/latest/tokio/macro.task_local.html) with one key difference. Any future annotated with
`.inherit_task_local()` will inherit the task local values of the task which spawned it. This does not inherit
values created by [`tokio::task_local`](https://docs.rs/tokio/latest/tokio/macro.task_local.html), it will only inherit values created by `inheritable_task_local`.

Here's a simple example

```rust
use tokio_inherit_task_local::{inheritable_task_local, FutureInheritTaskLocal as _};

inheritable_task_local! {
    pub static DEMO_VALUE: u32;
}

async fn foo() {
    let out = DEMO_VALUE
        .scope(5, async {
            tokio::spawn(async { DEMO_VALUE.with(|&v| v) }.inherit_task_local()).await
        })
        .await
        .unwrap();
    assert_eq!(out, 5);
}
```

Even though `DEMO_VALUE` was not defined for the spawned future, it was still able to inherit the value defined in
its parent. This happens thanks to the `.inherit_task_local()` method call. That method can be found in
`FutureInheritTaskLocal`.

These inherited values ***DO NOT*** need to be `Clone`. Child tasks will inherit counted references to the original value.