Deprecated - use CCNContentHandler instead.
A listener used to receive callbacks when data arrives matching one of our asynchronously-expressed Interests (expressed with CCNBase.expressInterest(Interest, CCNInterestListener)). Once the listener is called with matching data, the Interest is canceled. As a convenience, the listener can return a new Interest, which will be expressed on its behalf, using it as the callback listener when data is returned in response. This new Interest can be the same as the previous Interest, derived from it, or completely unrelated. Since data consumes Interest, there can only be a single response for one Interest expression.