Assuure Delegate is Send (#271)

src/rust/api/client.rs

@@ -103,7 +103,7 @@ pub struct ServerMessage {
 ///
 /// It contains methods to deal with all common issues, as well with the ones related to
 /// uploading media
-pub trait Delegate {
+pub trait Delegate: Send {
     /// Called at the beginning of any API request. The delegate should store the method
     /// information if he is interesting in knowing more context when further calls to it
     /// are made.

src/rust/lib.rs

@@ -97,6 +97,15 @@ bar\r\n\
             Ok(Chunk { first: 2, last: 42 })
         )
     }
+
+    #[test]
+    fn dyn_delegate_is_send() {
+        fn with_send(x: impl Send) {}
+
+        let mut dd = DefaultDelegate::default();
+        let dlg: &mut dyn Delegate = &mut dd;
+        with_send(dlg);
+    }
 }
 
 #[cfg(test)]