Wait for remaining drop tokens before breaking from event stream thread

There might still be some pending drop tokens after the receiving end of the event stream was closed. So we don't want to break from the receiver thread directly. Instead we keep it running until the control channel signals that it expects no more drop tokens by closing the `finished_drop_tokens` channel. This happens either when all required drop tokens were received, or because of a timeout.

apis/rust/node/src/daemon_connection/event_stream.rs

@@ -176,9 +176,16 @@ fn event_stream_loop(
                     ack_channel: drop_tx,
                 }) {
                     Ok(()) => {}
-                    Err(_) => {
-                        // receiving end of channel was closed
-                        break 'outer Ok(());
+                    Err(send_error) => {
+                        let event = send_error.into_inner();
+                        tracing::debug!(
+                            "event channel was closed already, could no forward `{event:?}`"
+                        );
+                        if finished_drop_tokens.is_disconnected() {
+                            // both the event stream and the dora node were dropped
+                            // -> break from the `event_stream_loop`
+                            break 'outer Ok(());
+                        }
                     }
                 }
 
@@ -220,6 +227,8 @@ fn event_stream_loop(
         }
     }
 }
+
+#[derive(Debug)]
 enum EventItem {
     NodeEvent {
         event: NodeEvent,

apis/rust/node/src/node.rs

@@ -236,6 +236,10 @@ impl Drop for DoraNode {
             }
         }
 
+        // close `finished_drop_tokens` to signal event stream thread that no
+        // more drop tokens are expected
+        self.finished_drop_tokens = flume::bounded(0).1;
+
         tracing::info!("reporting node stop for node `{}`", self.id);
         if let Err(err) = self.control_channel.report_stop() {
             tracing::error!("{err:?}")