protect generate and recover from u64->usize casting issues

src/ledger.rs

@@ -47,6 +47,7 @@ pub fn reconstruct_entries_from_blobs(blobs: VecDeque<SharedBlob>) -> bincode::R
     for blob in blobs {
         let entry = {
             let msg = blob.read().unwrap();
+
             deserialize(&msg.data()[..msg.meta.size])
         };