Fix Compositor concurrent initialization

It seems that initializing the compositor in a
different thread can cause issues in some environments.

futures/src/backend/native/smol.rs

@@ -12,6 +12,10 @@ impl crate::Executor for Executor {
     fn spawn(&self, future: impl Future<Output = ()> + Send + 'static) {
         smol::spawn(future).detach();
     }
+
+    fn block_on<T>(&self, future: impl Future<Output = T>) -> T {
+        smol::block_on(future)
+    }
 }
 
 pub mod time {

futures/src/backend/native/thread_pool.rs

@@ -11,6 +11,10 @@ impl crate::Executor for Executor {
     fn spawn(&self, future: impl Future<Output = ()> + Send + 'static) {
         self.spawn_ok(future);
     }
+
+    fn block_on<T>(&self, future: impl Future<Output = T>) -> T {
+        futures::executor::block_on(future)
+    }
 }
 
 pub mod time {

futures/src/backend/native/tokio.rs

@@ -17,6 +17,10 @@ impl crate::Executor for Executor {
         let _guard = tokio::runtime::Runtime::enter(self);
         f()
     }
+
+    fn block_on<T>(&self, future: impl Future<Output = T>) -> T {
+        self.block_on(future)
+    }
 }
 
 pub mod time {

futures/src/backend/null.rs

@@ -11,6 +11,11 @@ impl crate::Executor for Executor {
     }
 
     fn spawn(&self, _future: impl Future<Output = ()> + MaybeSend + 'static) {}
+
+    #[cfg(not(target_arch = "wasm32"))]
+    fn block_on<T>(&self, _future: impl Future<Output = T>) -> T {
+        unimplemented!()
+    }
 }
 
 pub mod time {

futures/src/executor.rs

@@ -11,6 +11,10 @@ pub trait Executor: Sized {
     /// Spawns a future in the [`Executor`].
     fn spawn(&self, future: impl Future<Output = ()> + MaybeSend + 'static);
 
+    /// Runs a future to completion in the current thread within the [`Executor`].
+    #[cfg(not(target_arch = "wasm32"))]
+    fn block_on<T>(&self, future: impl Future<Output = T>) -> T;
+
     /// Runs the given closure inside the [`Executor`].
     ///
     /// Some executors, like `tokio`, require some global state to be in place

futures/src/runtime.rs

@@ -50,12 +50,10 @@ where
         self.executor.enter(f)
     }
 
-    /// Spawns a [`Future`] in the [`Runtime`].
-    pub fn spawn(
-        &mut self,
-        future: impl Future<Output = ()> + MaybeSend + 'static,
-    ) {
-        self.executor.spawn(future);
+    /// Runs a future to completion in the current thread within the [`Runtime`].
+    #[cfg(not(target_arch = "wasm32"))]
+    pub fn block_on<T>(&mut self, future: impl Future<Output = T>) -> T {
+        self.executor.block_on(future)
     }
 
     /// Runs a [`Stream`] in the [`Runtime`] until completion.