Conversations now fully monitor the Folder for both additions and removals of messages.
This exposed a couple of bugs in the database code, which are fixed here as well. I also
used this opportunity to clean up some of the internal Conversations code, simplifying Node
management. #4333 will be a big boost here when implemented.
addressing.
Positional addressing is a nightmare for a lot of reasons, especially keeping positions
up-to-date as the Folder mutates. Now, positions are returned with the email but for
advisory reasons only, and do not keep up-to-date. It is expected that a client will use
positional addressing to "bootstrap" the application's data store, then use EmailIdentifier
addressing to traverse the Folder's contents.
Prior commit did not completely fix the problem in the case where a remote folder open took
a long time. This bulletproofs the solution, but does mean that there will be some
situations where FAST messages return with EmailLocations that radically change in the near
future. As the contract allows for any changes whatsoever, this is acceptable.
