2 files changed, 35 insertions, 4 deletions
diff --git a/core/src/runtime.rs b/futures/src/runtime.rs
index 31234d11..bc1ad8ac 100644
--- a/core/src/runtime.rs
+++ b/futures/src/runtime.rs
@@ -1,3 +1,4 @@
+//! Run commands and subscriptions.
 mod executor;
 
 pub use executor::Executor;
@@ -10,8 +11,8 @@ use std::marker::PhantomData;
 #[derive(Debug)]
 pub struct Runtime<Hasher, Event, Executor, Receiver, Message> {
     executor: Executor,
-    subscriptions: subscription::Tracker<Hasher, Event>,
     receiver: Receiver,
+    subscriptions: subscription::Tracker<Hasher, Event>,
     _message: PhantomData<Message>,
 }
 
@@ -28,15 +29,19 @@ where
         + 'static,
     Message: Send + 'static,
 {
-    pub fn new(receiver: Receiver) -> Self {
+    pub fn new(executor: Executor, receiver: Receiver) -> Self {
         Self {
-            executor: Executor::new(),
-            subscriptions: subscription::Tracker::new(),
+            executor,
             receiver,
+            subscriptions: subscription::Tracker::new(),
             _message: PhantomData,
         }
     }
 
+    pub fn enter<R>(&self, f: impl FnOnce() -> R) -> R {
+        self.executor.enter(f)
+    }
+
     pub fn spawn(&mut self, command: Command<Message>) {
         use futures::{FutureExt, SinkExt};
 
diff --git a/futures/src/runtime/executor.rs b/futures/src/runtime/executor.rs
new file mode 100644
index 00000000..855aa105
--- /dev/null
+++ b/futures/src/runtime/executor.rs
@@ -0,0 +1,26 @@
+use futures::Future;
+
+pub trait Executor {
+    fn spawn(&self, future: impl Future<Output = ()> + Send + 'static);
+
+    fn enter<R>(&self, f: impl FnOnce() -> R) -> R {
+        f()
+    }
+}
+
+impl Executor for futures::executor::ThreadPool {
+    fn spawn(&self, future: impl Future<Output = ()> + Send + 'static) {
+        self.spawn_ok(future);
+    }
+}
+
+#[cfg(feature = "tokio")]
+impl Executor for tokio::runtime::Runtime {
+    fn spawn(&self, future: impl Future<Output = ()> + Send + 'static) {
+        let _ = tokio::runtime::Runtime::spawn(self, future);
+    }
+
+    fn enter<R>(&self, f: impl FnOnce() -> R) -> R {
+        tokio::runtime::Runtime::enter(self, f)
+    }
+}