actix 0.13.5

Actor framework for Rust
Documentation
## 0.10.0

- `SinkWrite::write` no longer return a Result, instead it returns an `Option<I>` containing the item that had attempted to be sent if the sink is closing or closed.

  Before:

  ```rust
  self.sink.write(data).unwrap();
  ```

  After:

  ```rust
  let _ = self.sink.write(data);
  ```

## 0.7.9

- `actix` no longer re-exports itself in `actix::prelude` to avoid conflicts with 2018 editions. Please access it through your `extern crate actix` import when necessary

## 0.7.6

- `trust-dns-resolver` dependency was bumped to version 0.10.0. If you use a custom resolver, you will need to switch your `ResolverConfig` and `ResolverOpts` to `trust-dns-resolver` 0.10.0 instead of 0.9.1.

## 0.7

- `Addr` get refactored. `Syn` and `Unsync` removed. all addresses are `Syn` now, only `Addr<Actor>` exists

- `Arbiter` uses `tokio::runtime::current_thread`

- `Arbiter::arbiter()` renamed to `Arbiter::current()`

- `Arbiter::handle()` get removed use `Arbiter::spawn()` instead or you can send `Execute` message to the `System`.

- `Arbiter::system_arbiter()` get removed use `System::arbiter()` instead.

- Use `actix::actors::resolver` instead of `actix::actors::resolver::{Connect, ConnectAddr, Connector, ConnectorError, Resolve};`

- `actix::actors::resolver::Connector` renamed to `actix::actors::resolver::Resolver`

- `actix::actors::resolver::ConnectorError` renamed to `actix::actors::resolver::ResolverError`