tracing-actix 0.4.0

# tracing-actix  [![crates.io](https://meritbadge.herokuapp.com/tracing-actix)](https://crates.io/crates/tracing-actix) [![docs.rs](https://docs.rs/tracing-actix/badge.svg)](https://docs.rs/tracing-actix/) [![Build Status](https://travis-ci.org/zenria/tracing-actix.svg?branch=master)](https://travis-ci.org/zenria/tracing-actix)

_experimental tracing support for actix actor futures_

Inspired from 0.0.1-alpha.1 version of 
[tracing-futures](https://github.com/tokio-rs/tracing/tree/master/tracing-futures)

## License

Licensed under either of

 * Apache License, Version 2.0
   ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
 * MIT license
   ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)

at your option.

## Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in the work by you, as defined in the Apache-2.0 license, shall be
dual licensed as above, without any additional terms or conditions.