You can create custom sinks, which can be passed to sink or
sink! by defining two methods: SignalOperators.initsink
and SignalOperators.sink_helper!. The first method is called when a
call to sink is made (e.g. sink(MyCustomSink)). The second method is
called inside sink! and provides the core operation to write blocks of
frames to the sink. There is already a method of sink_helper! defined for
AbstractArray objects, so you likely do not need to implement it if your
custom sink is an AbtractArray.
You may also want to implement a constructor of the sink type that takes a
single argument x of type SignalOperators.AbstractSignal. This should
generally just call sink(x,CustomSink).
!!! note
Implementing `initsink` is not strictly necessary. If you do not implement
`initsink` you will only be able to write to the sink using `sink!`.