fix: sub memory leak

src/net/sample.c

@@ -88,7 +88,7 @@ _z_sample_t _z_sample_create(const _z_keyexpr_t *key, const _z_slice_t *payload,
     s.kind = kind;
     s.timestamp = timestamp;
     s.qos = qos;
-    s.attachment = _z_bytes_duplicate(&att);
+    s.attachment._slice = _z_slice_steal((_z_slice_t *)&att._slice);
     return s;
 }
 #else