selects the MIX_INIT_FLAC subsystem
selects the MIX_INIT_MOD subsystem
selects the MIX_INIT_MP3 subsystem
selects the MIX_INIT_OGG subsystem
selects the MIX_INIT_FLUIDSYNTH (for SDL_mixer below 2.0.2) / MIX_INIT_MID subsystem
selects the MIX_INIT_OPUS subsystem (from SDL_mixer 2.0.4)
selects every available subsystem
dsdl2.SDLException if any selected subsystem failed to initialize
dsdl2.mixer.init(everything : true);
Wraps Mix_Init which initializes selected SDL2_mixer audio format subsystems