add fail-resend support.

lichao

2021-04-12 1b52f1cb8c47dd2c0195d2fd65d7b6a4c2f10704

 .gitignore

@@ -1,4 +1,8 @@
*.un~
build/
debug/
release/
Makefile
utest/utest
*.bak
gmon.out