Function wait 

pub async fn wait<T, F>(task: F) -> T
where
    F: FnOnce() -> T + Send + 'static,
    T: Send + 'static,

Create a parallel task that blocks awaiting for an IO operation, the task starts on the first .await.

Parallel

The task runs in the blocking thread-pool which is optimized for awaiting blocking operations. If the task is computation heavy you should use run and then wait inside that task for the parts that are blocking.

Examples

task::wait(|| std::fs::read_to_string("file.txt")).await

The example reads a file, that is a blocking file IO operation, most of the time is spend waiting for the operating system, so we offload this to a wait task. The task can be .await inside a run task or inside one of the UI tasks like in a async event handler.

Async Read/Write

For std::io::Read and std::io::Write operations you can also use io and fs alternatives when you don’t have or want the full file in memory or when you want to apply multiple operations to the file.

Panic Propagation

If the task panics the panic is resumed in the awaiting thread using resume_unwind. You can use wait_catch to get the panic as an error instead.