try_add_current_rnext_key
try_add_current_rnext_key("closed socket, add + change current key",
try_add_current_rnext_key("closed socket, add + change rnext key",
try_add_current_rnext_key("listen socket, add + change current key",
try_add_current_rnext_key("listen socket, add + change rnext key",