prepare rt v2.0.0-beta.3

actix-rt/CHANGES.md

@@ -1,6 +1,9 @@
 # Changes
 
 ## Unreleased - 2021-xx-xx
+
+
+## 2.0.0-beta.3 - 2021-01-31
 * Remove `run_in_tokio`, `attach_to_tokio` and `AsyncSystemRunner`. [#253]
 * Return `JoinHandle` from `actix_rt::spawn`. [#253]
 * Remove old `Arbiter::spawn`. Implementation is now inlined into `actix_rt::spawn`. [#253]

actix-rt/Cargo.toml

@@ -1,7 +1,10 @@
 [package]
 name = "actix-rt"
-version = "2.0.0-beta.2"
+version = "2.0.0-beta.3"
-authors = ["Nikolay Kim <fafhrd91@gmail.com>"]
+authors = [
+    "Nikolay Kim <fafhrd91@gmail.com>",
+    "Rob Ede <robjtede@icloud.com>",
+]
 description = "Tokio-based single-thread async runtime for the Actix ecosystem"
 keywords = ["network", "framework", "async", "futures"]
 homepage = "https://actix.rs"

actix-rt/README.md

@@ -0,0 +1,7 @@
+# actix-rt
+
+> Tokio-based single-thread async runtime for the Actix ecosystem.
+
+See documentation for detailed explanations these components: [https://docs.rs/actix-rt][docs].
+
+[docs]: https://docs.rs/actix-rt

actix-rt/src/lib.rs

@@ -1,4 +1,37 @@
 //! Tokio-based single-thread async runtime for the Actix ecosystem.
+//!
+//! In most parts of the the Actix ecosystem, it has been chosen to use !Send futures. For this
+//! reason, a single-threaded runtime is appropriate since it is guaranteed that futures will not
+//! be moved between threads. This can result in small performance improvements over cases where
+//! atomics would otherwise be needed.
+//!
+//! To achieve similar performance to multi-threaded, work-stealing runtimes, applications
+//! using `actix-rt` will create multiple, mostly disconnected, single-threaded runtimes.
+//! This approach has good performance characteristics for workloads where the majority of tasks
+//! have similar runtime expense.
+//!
+//! The disadvantage is that idle threads will not steal work from very busy, stuck or otherwise
+//! backlogged threads. Tasks that are disproportionately expensive should be offloaded to the
+//! blocking thread-pool using [`task::spawn_blocking`].
+//!
+//! # Examples
+//! ```
+//! use std::sync::mpsc;
+//! use actix_rt::{Arbiter, System};
+//!
+//! let _ = System::new();
+//!
+//! let (tx, rx) = mpsc::channel::<u32>();
+//!
+//! let arbiter = Arbiter::new();
+//! arbiter.spawn_fn(move || tx.send(42).unwrap());
+//!
+//! let num = rx.recv().unwrap();
+//! assert_eq!(num, 42);
+//!
+//! arbiter.stop();
+//! arbiter.join().unwrap();
+//! ```
 
 #![deny(rust_2018_idioms, nonstandard_style)]
 #![allow(clippy::type_complexity)]