Hi,

The lt_donhave extension is very useful for implementations that keep a bounded amount of data:

If a peer discards a piece due to memory pressure, in the basic BitTorrent protocol it can either ignore requests for the missing piece (which might cause a peer to stall), or drop connections that request a missing piece.  (With the FAST extension, it can send a Reject message, but that is still far from optimal).

The lt_donthave extension allows a peer to advertise that it has dropped a piece.  It is very easy to implement (it's just the opposite of the HAVE message), and solves the issue quite nicely.

Pleae implement lt_donthave.

Completely second this

Thanks!