refactor(errors): improve message and add logging when sending tree from backend panics

crates/core/src/blob/tree.rs

@@ -13,6 +13,7 @@ use derive_setters::Setters;
 use ignore::overrides::{Override, OverrideBuilder};
 use ignore::Match;
 
+use log::debug;
 use serde::{Deserialize, Deserializer};
 use serde_derive::Serialize;
 
@@ -689,9 +690,17 @@ impl<P: Progress> TreeStreamerOnce<P> {
             let out_tx = out_tx.clone();
             let _join_handle = std::thread::spawn(move || {
                 for (path, id, count) in in_rx {
-                    out_tx
-                        .send(Tree::from_backend(&be, &index, id).map(|tree| (path, tree, count)))
-                        .unwrap();
+                    debug!("Loading tree {id} from {path:?} with count {count}");
+
+                    if let Err(err) = out_tx.try_send(
+                        Tree::from_backend(&be, &index, id).map(|tree| (path, tree, count)),
+                    ) {
+                        panic!("
+                        Sending tree {id} on channel failed: {err}. 
+
+                        This should not happen! Please report it to the developers: https://github.com/rustic-rs/rustic_core/issues/new
+                        ");
+                    }
                 }
             });
         }