Buffer pending acks (acks for addressed, bcast_acks for broadcast,
ACK_BUFFER_CAP=256, overflow drops oldest), skip a released-duplicate
offer in accept(), and emit Ack frames in next_frame after a due summary
and before addressed/broadcast traffic, draining up to ACK_IDS_CAP ids
per destination and splitting across frames to fit mtu.
Release custody on an Ack only when the Ack confirms delivery to the
intended recipient: an Ack from a peer that merely holds an
epidemic-forwarded copy no longer releases custody, so the local copy
stays available to forward toward the recipient once the only contact to
it closes.
kyle
fafda104ea