registers an image consumer with the image producer for accessing
the image data during a later reconstruction of the image.
The image producer may, at its discretion, start delivering the
image data to the consumer using the XImageConsumer
interface immediately, or when the next available image reconstruction
is triggered by a call to the startProduction method.
removes the given XImageConsumer
callback from the list of consumers currently registered to receive
image data.
It is not considered an error to remove a consumer that is not
currently registered. The image producer should stop sending data
to this consumer as soon as it is feasible.
registers the given image consumer as a consumer
and starts an immediate reconstruction of the image data.
The image data will then be delivered to this consumer and any other
consumer which may have already been registered with the producer.
This method differs from the addConsumer method in that a reproduction of
the image data should be triggered as soon as possible.
