Via @crstauf on #301 (comment):

Possible to add qm/start/qm/stop onto a hook, and if there's no param (function name) provided, assume current_action()?

QM could enable this via a wrapper function such as qm_start() and qm_stop() which would then be used like this:

add_action( 'after_setup_theme', 'qm_start', 0 );
add_action( 'after_setup_theme', 'qm_stop', 999 );

Maybe even only require the start action and QM adds the stop action itself.