Alsa pause resume
Alsa sink uses snd_pcm_pause upon pause/resume, if hardware supports it. This relies on audiosink exposes more methods.
By using snd_pcm_pause the ALSA state will be pause, telling other clients correct status. Also, using pause there is no need of dropping frames from ALSA buffer and refill it again, pause will leave no glitch nor play until buffer is empty.