Pause the music stream.
Pausing the music stream will prevent further playback of the assigned music object, but will maintain the object's current mixing position. When resumed, this channel will continue to mix the music where it left off.
Paused music can be resumed by calling Mix_ResumeMusic().
It is legal to halt paused music. Playing a new music object when music is paused will replace the current music and unpause the music stream.
This function is available since SDL_mixer 2.0.0.