An ALLEGRO_SAMPLE_INSTANCE object represents a playable instance of a
predefined sound effect.
It holds information pertaining to the looping mode, loop start/end
points, playing position, etc.
An instance uses the data from an ALLEGRO_SAMPLE(3) object.
Multiple instances may be created from the same ALLEGRO_SAMPLE.
An ALLEGRO_SAMPLE must not be destroyed while there are instances which
To be played, an ALLEGRO_SAMPLE_INSTANCE object must be attached to an
ALLEGRO_VOICE(3) object, or to an ALLEGRO_MIXER(3) object which is
itself attached to an ALLEGRO_VOICE object (or to another ALLEGRO_MIXER
object which is attached to an ALLEGRO_VOICE object, etc).