t / t5100 / patch0018on commit read_packed_refs(): use mmap to read the `packed-refs` file (49a03ef)
   1diff --git a/foo b/foo
   2index e69de29..d95f3ad 100644
   3--- a/foo
   4+++ b/foo
   5@@ -0,0 +1 @@
   6+content