new changes per message

1 files changed, 5 insertions, 3 deletions

diff --git a/src/document/sync.rs b/src/document/sync.rs
index 0aeec83..1f61f70 100644
--- a/src/document/sync.rs
+++ b/src/document/sync.rs
@@ -427,17 +427,19 @@ impl SyncSession {
     /// the peer's own changes back. A delta comes outside the sync protocol, so
     /// Automerge would think the peer lacks all of it, and offer it back as a delta of
     /// our own. Counted as sent (`sent_hashes`), they don't; Automerge forgets them as
-    /// sent once the peer's heads cover them. (Changes kept until their predecessors came,
+    /// sent once the peer's heads cover them. Returns how many changes that is. (Changes kept until their predecessors came,
     /// from another peer, count too: should this one lack them, it asks, and gets them,
     /// `resend_if_needed`.)
     pub(crate) fn came_from_peer(
         &mut self,
         doc: &Document,
         before: &[crate::document::ChangeHash],
-    ) {
-        for change in doc.get_changes_meta(before) {
+    ) -> usize {
+        let changes = doc.get_changes_meta(before);
+        for change in &changes {
             self.state.sent_hashes.insert(change.hash);
         }
+        changes.len()
     }
 
     /// Of the changes in `doc` beyond `from`, how many the peer has too, as far as we