Set the current position in the music stream, in seconds.
int Mix_SetMusicPosition(double position);
the new position, in seconds (as a double).
Returns 0 if successful, or -1 if it failed or not implemented.
To convert from milliseconds, divide by 1000.0.
This function is only implemented for MOD music formats (set pattern order number) and for WAV, OGG, FLAC, MP3, and MODPLUG music at the moment.
This function is available since SDL_mixer 2.0.0.