build(deps): minimize `futures` deps by using `futures-channel` and `futures-util` directly

actix-rt/Cargo.toml

@@ -18,6 +18,7 @@ path = "src/lib.rs"
 [dependencies]
 actix-macros = "0.1.0"
 actix-threadpool = "0.3"
-futures = "0.3.1"
+futures-channel = "0.3.1"
+futures-util = { version = "0.3.1", default-features = false }
 copyless = "0.1.4"
 tokio = { version = "0.2.6", default-features=false, features = ["rt-core", "rt-util", "io-driver", "tcp", "uds", "udp", "time", "signal", "stream"] }

actix-rt/src/arbiter.rs

@@ -6,9 +6,9 @@ use std::sync::atomic::{AtomicUsize, Ordering};
 use std::task::{Context, Poll};
 use std::{fmt, thread};
 
-use futures::channel::mpsc::{unbounded, UnboundedReceiver, UnboundedSender};
-use futures::channel::oneshot::{channel, Canceled, Sender};
-use futures::{future, Future, FutureExt, Stream};
+use futures_channel::mpsc::{unbounded, UnboundedReceiver, UnboundedSender};
+use futures_channel::oneshot::{channel, Canceled, Sender};
+use futures_util::{future::{self, Future, FutureExt}, stream::Stream};
 
 use crate::runtime::Runtime;
 use crate::system::System;

actix-rt/src/builder.rs

@@ -1,9 +1,9 @@
 use std::borrow::Cow;
 use std::io;
 
-use futures::channel::mpsc::unbounded;
-use futures::channel::oneshot::{channel, Receiver};
-use futures::future::{lazy, Future, FutureExt};
+use futures_channel::mpsc::unbounded;
+use futures_channel::oneshot::{channel, Receiver};
+use futures_util::future::{lazy, Future, FutureExt};
 use tokio::task::LocalSet;
 
 use crate::arbiter::{Arbiter, SystemArbiter};

actix-rt/src/lib.rs

@@ -25,7 +25,7 @@ pub use actix_threadpool as blocking;
 /// This function panics if actix system is not running.
 pub fn spawn<F>(f: F)
 where
-    F: futures::Future<Output = ()> + 'static,
+    F: futures_util::future::Future<Output = ()> + 'static,
 {
     if !System::is_set() {
         panic!("System is not running");

actix-rt/src/system.rs

@@ -3,7 +3,7 @@ use std::future::Future;
 use std::io;
 use std::sync::atomic::{AtomicUsize, Ordering};
 
-use futures::channel::mpsc::UnboundedSender;
+use futures_channel::mpsc::UnboundedSender;
 use tokio::task::LocalSet;
 
 use crate::arbiter::{Arbiter, SystemCommand};