diff --git a/ufotofu/src/local_nb.rs b/ufotofu/src/local_nb.rs
index 5a30380..a55afcb 100644
--- a/ufotofu/src/local_nb.rs
+++ b/ufotofu/src/local_nb.rs
@@ -413,7 +413,7 @@ where
             let mut produced_so_far = 0;
 
             while produced_so_far < buf.len() {
-                match self.bulk_produce(buf).await {
+                match self.bulk_produce(&mut buf[produced_so_far..]).await {
                     Ok(Left(count)) => produced_so_far += count,
                     Ok(Right(fin)) => {
                         return Err(OverwriteFullSliceError {