Optimization: stop the streams when there is only silence about immerse HOT 1 CLOSED

One reason might be: do not 'use' the hardware more than needed. But this is not really useful, since expected use is constant while working with the application. Shutting down properly is responsibility of the application builder. It might be possible to start/stop Immerse explicitly, but implicitly seems error prone. Only valid reason might be restarting all streams to sync up again. But we can never trust that happens often enough, for instance with continuous background music. So that needs another feature anyway. Closing this issue and new ones should be created if something like this is needed explicitly later.

from immerse.