future

问题 I am attempting to create simplest possible example that can get async fn hello() to eventually print out Hello World! . This should happen without any external dependency like tokio , just plain Rust and std . Bonus points if we can get it done without ever using unsafe . #![feature(async_await)] async fn hello() { println!("Hello, World!"); } fn main() { let task = hello(); // Something beautiful happens here, and `Hello, World!` is printed on screen. } I know async/await is still a nightly

问题 When I make a future , or apply methods like onSuccess and map , I can specify ExecutionContext for them. For example, val f = future { // code } executionContext f.map(someFunction)(executionContext) f onSuccess { // code } executionContext However, if I use a for-comprehension of future, how can I specify ExecutionContext for the yield part? for { f <- future1 g <- future2 } yield { // code to be executed after future1 onSuccess and future2 onSuccess // What ExecutionContext runs this code?

问题 When I make a future , or apply methods like onSuccess and map , I can specify ExecutionContext for them. For example, val f = future { // code } executionContext f.map(someFunction)(executionContext) f onSuccess { // code } executionContext However, if I use a for-comprehension of future, how can I specify ExecutionContext for the yield part? for { f <- future1 g <- future2 } yield { // code to be executed after future1 onSuccess and future2 onSuccess // What ExecutionContext runs this code?

问题 When I run my app it throws a lot of errors, and the red/yellow error screen on my device, which refreshes automatically and shows me the expected output then. From the log I can see that first my object is return as null, which somehow later updates and I get the output. I have recently started Android Dev (Flutter) I tried to follow a number of online guides and also read related questions on async responses but no troubleshooting has been helping me. My biggest problem being that I can't

问题 When I run my app it throws a lot of errors, and the red/yellow error screen on my device, which refreshes automatically and shows me the expected output then. From the log I can see that first my object is return as null, which somehow later updates and I get the output. I have recently started Android Dev (Flutter) I tried to follow a number of online guides and also read related questions on async responses but no troubleshooting has been helping me. My biggest problem being that I can't

问题 When I run my app it throws a lot of errors, and the red/yellow error screen on my device, which refreshes automatically and shows me the expected output then. From the log I can see that first my object is return as null, which somehow later updates and I get the output. I have recently started Android Dev (Flutter) I tried to follow a number of online guides and also read related questions on async responses but no troubleshooting has been helping me. My biggest problem being that I can't

问题 I have created a simple test scenario that shows this: class Test extends AsyncFunSuite { test("async test") { val f = Future { val thread = new Thread { override def run(): Unit = { println("OKAYY") } } thread.start() } Await.result(f, Duration.Inf) Future { assert(true) } } } When executing this, the test runs forever and never completes. 回答1: You will see the same behavior with all asynchronous testing in ScalaTest (AsyncFeatureSpec, AsyncFlatSpec, AsyncFreeSpec, AsyncFunSpec,

问题 I'd like to take a regular iterator and turn it into a stream so that I can do further stream processing. The trouble is that I may have an iterator or an error to deal with. I think I'm pretty close with this: #[macro_use] extern crate log; extern crate futures; // 0.1.21 extern crate tokio; use futures::prelude::*; use futures::{future, stream}; use std::fmt::Debug; use std::net::{SocketAddr, ToSocketAddrs}; fn resolve(addrs: impl ToSocketAddrs + Debug) -> impl Stream<Item = SocketAddr,

问题 I'm trying to use scalatest Asynchronous Test Suites, but aside from some restrictions over setting timeout and what not, I don't see what does the test suite actually add. I wonder if anyone versed into asynchronous testing with scalatest could quickly explain the differences between Asynchronous Test Suites and org.scalatest.concurrent . What do async test suites actually add over org.scalatest.concurrent ? Is one approach better over the other? 回答1: We compare the following ScalaTest

问题 I'm trying to use scalatest Asynchronous Test Suites, but aside from some restrictions over setting timeout and what not, I don't see what does the test suite actually add. I wonder if anyone versed into asynchronous testing with scalatest could quickly explain the differences between Asynchronous Test Suites and org.scalatest.concurrent . What do async test suites actually add over org.scalatest.concurrent ? Is one approach better over the other? 回答1: We compare the following ScalaTest