allow overwriting existing sdk shutdown manager

common/client-core/src/client/base_client/mod.rs

@@ -1005,7 +1005,7 @@ where
         // or get one from the registry
         let shutdown_tracker = match self.shutdown {
             Some(parent_tracker) => parent_tracker.clone(),
-            None => nym_task::get_sdk_shutdown_tracker()?,
+            None => nym_task::create_sdk_shutdown_tracker()?,
         };
 
         Self::start_event_control(self.event_tx, event_receiver, &shutdown_tracker);

common/client-core/src/client/cover_traffic_stream.rs

@@ -205,7 +205,7 @@ impl LoopCoverTrafficStream<OsRng> {
                 TrySendError::Full(_) => {
                     // This isn't a problem, if the channel is full means we're already sending the
                     // max amount of messages downstream can handle.
-                    tracing::debug!("Failed to send cover message - channel full");
+                    tracing::trace!("Failed to send cover message - channel full");
                 }
                 TrySendError::Closed(_) => {
                     tracing::warn!("Failed to send cover message - channel closed");