Introduce MaybeSend trait in iced_futures

It allows to clean up all the `trait_aliases` modules!

futures/src/subscription/tracker.rs

@@ -1,52 +1,8 @@
-use crate::{BoxFuture, Subscription};
+use crate::{BoxFuture, MaybeSend, Subscription};
 
 use futures::{channel::mpsc, sink::Sink};
 use std::{collections::HashMap, marker::PhantomData};
 
-#[cfg(not(target_arch = "wasm32"))]
-mod trait_aliases {
-    use super::*;
-
-    pub trait TrackerMessage: Send + 'static {}
-
-    impl<T> TrackerMessage for T where T: Send + 'static {}
-
-    pub trait TrackerMessageReceiver<Message: TrackerMessage>:
-        Sink<Message, Error = mpsc::SendError> + Unpin + Send + Clone + 'static
-    {
-    }
-
-    impl<Message: TrackerMessage, T> TrackerMessageReceiver<Message> for T where
-        T: Sink<Message, Error = mpsc::SendError>
-            + Unpin
-            + Send
-            + Clone
-            + 'static
-    {
-    }
-}
-
-#[cfg(target_arch = "wasm32")]
-mod trait_aliases {
-    use super::*;
-
-    pub trait TrackerMessage: 'static {}
-
-    impl<T> TrackerMessage for T where T: 'static {}
-
-    pub trait TrackerMessageReceiver<Message: TrackerMessage>:
-        Sink<Message, Error = mpsc::SendError> + Unpin + Clone + 'static
-    {
-    }
-
-    impl<Message: TrackerMessage, T> TrackerMessageReceiver<Message> for T where
-        T: Sink<Message, Error = mpsc::SendError> + Unpin + Clone + 'static
-    {
-    }
-}
-
-pub use trait_aliases::{TrackerMessage, TrackerMessageReceiver};
-
 /// A registry of subscription streams.
 ///
 /// If you have an application that continuously returns a [`Subscription`],
@@ -101,8 +57,12 @@ where
         receiver: Receiver,
     ) -> Vec<BoxFuture<()>>
     where
-        Message: TrackerMessage,
-        Receiver: TrackerMessageReceiver<Message>,
+        Message: 'static + MaybeSend,
+        Receiver: 'static
+            + Sink<Message, Error = mpsc::SendError>
+            + Unpin
+            + MaybeSend
+            + Clone,
     {
         use futures::{future::FutureExt, stream::StreamExt};