tree: prefix iter fn added

src/tree.rs

@@ -223,6 +223,22 @@ impl Tree {
     {
         TreeIter::range(self, range)
     }
+
+    /// Returns an iterator over the Tree for the provided key prefix.
+    pub fn prefix_iter(&self, k: &[u8]) -> TreeIter {
+        #[cfg(feature = "sled-backend")]
+        {
+            TreeIter {
+                iter: self.tree.scan_prefix(k),
+            }
+        }
+        #[cfg(feature = "fjall-backend")]
+        {
+            TreeIter {
+                iter: self.tree.prefix(k),
+            }
+        }
+    }
 }
 
 impl std::fmt::Debug for Tree {