This feature adds the support for rr in mtr. These 2 options are added
--rr         run   the mysqld in rr record mode
--rr_option= run the rr with custom record option, for multiple
             options use --rr_option= for each option.
             For example
              ./mtr main.view --rr_option=-h --rr_option=-u --rr_option=-c=23
--boot-rr    run the mysqld performing bootstrap in rr record mode

Recording are stored in mysql-test/var/rr folder.
To run recording please run
rr replay var/rr/mysql-X

Limitations
Restart will create a new recording.
Repeat will work on same recording , So might be harder to debug.
If test create the multiple instance of mariadb all will be stored in var/rr