feat(executor): add cosmic::executor::Default

src/single_thread_executor.rs

@@ -1,28 +0,0 @@
-use std::{future::Future, thread};
-
-#[cfg(feature = "tokio")]
-pub struct SingleThreadExecutor(tokio::runtime::Runtime);
-
-#[cfg(feature = "tokio")]
-impl iced_native::Executor for SingleThreadExecutor {
-    fn new() -> Result<Self, iced::futures::io::Error> {
-        // Current thread executor requires calling `block_on` to actually run
-        // futures. Main thread is busy with things other than running futures,
-        // so spawn a single worker thread.
-        Ok(Self(
-            tokio::runtime::Builder::new_multi_thread()
-                .worker_threads(1)
-                .enable_all()
-                .build()?,
-        ))
-    }
-
-    fn spawn(&self, future: impl Future<Output = ()> + Send + 'static) {
-        let _ = self.0.spawn(future);
-    }
-
-    fn enter<R>(&self, f: impl FnOnce() -> R) -> R {
-        let _guard = self.0.enter();
-        f()
-    }
-}