Suspend or resume the specified sink (which my be
specified either by its symbolic name, or by its numeric index),
depending whether 1 (suspend) or 0 (resume) is passed as last
argument. Suspending a sink will pause all playback. Depending
on the module implementing the sink this might have the effect
that the underlying device is closed, making it available for
other applications to use. The exact behaviour depends on the
module.