Allow specifying a custom executor

src/application.rs

@@ -30,6 +30,8 @@
 //!     ]
 //! }
 //! ```
+use iced_futures::Executor;
+
 use crate::program::{self, Program};
 use crate::window;
 use crate::{Element, Font, Result, Settings, Size, Subscription, Task};
@@ -376,6 +378,22 @@ impl<P: Program> Application<P> {
             window: self.window,
         }
     }
+
+    /// Sets the executor of the [`Application`].
+    pub fn executor<E>(
+        self,
+    ) -> Application<
+        impl Program<State = P::State, Message = P::Message, Theme = P::Theme>,
+    >
+    where
+        E: Executor,
+    {
+        Application {
+            raw: program::with_executor::<P, E>(self.raw),
+            settings: self.settings,
+            window: self.window,
+        }
+    }
 }
 
 /// The title logic of some [`Application`].