This class provides a hook for general objects to behave like Stream objects.
usual stream messages (i.e. nextPut:, nextPutAll: etc).
passing the argument of nextPut: as block argument.
These blocks are to be provided by the user of the ActorStream.
Example use is in the Transcript, which is made Stream-like this way.
parts of the collection are asked for.
the nextPutAllBlock with something as argument.
the nextPutLineBlock with something as argument.
return a readStream from the receiver.
Since this is (hopefully) already a readStream, return self.
define the block to be evaluated for every nextPutAll-message.
define the block to be evaluated for every nextPutLineBlock-message.