ready to make a packfile, it will blindly ACK all 'have' obj-ids
back to the client.
- * the server will then send a 'NACK' and then wait for another response
+ * the server will then send a 'NAK' and then wait for another response
from the client - either a 'done' or another list of 'have' lines.
In multi_ack_detailed mode: