`scm_prompt_info` function -- performance issue

[username4gh]

because of PS1=[\j] \u [\e[32m]${PWD}[\e[0m] $(scm_prompt_info '(%s)')$

so every time the shell prints out the prompt-line, it will execute the scm_prompt_info function, normally it won't bring any issue, but while working under some large git-repo directory, the scm_prompt_info function is really slow, so it's might need a convenient way of disable-enable this feature.