Smack 4.4.6 NegotiationProgress callback implementation for IncomingFileTransfer

In smack OutgoingFileTransfer, there is callback i.e. NegotiationProgress() that allows app to get updated on the progress of the outgoing file transfer status.
Note: In OutgoingFileTransfer, good to have a stream byte sending progress callback e.g. ProgressListener like jingle file transfer.

However found that there is no such similar callback implementation for IncmongFileTransfer.
Any reason why the callback is not implemented for IncmongFileTransfer?

Without the NegotiationProgress, aTalk needs to running thread at 10ms interval, just to emulate the NegotiationProgress and ProgressListener callback.

In the case of Jingle file transfer implementation, there are JingleSessionListener and ProgressListener cater for both the outgoing and incoming file transfer.