[bind10-dev] revised in-memory NSEC task plans

[JINMEI Tatuya / 神明達哉]

As discussed in today's meeting, we seem to want to maximize the
concurrency in handling the current NSEC-related tickets.  This is my
proposal of revised plan:

- immediately start #1810.  Feature-wise there's no dependency for
  this task.  As commented, it might be optimal if we wait for #1809,
  but we're now prioritizing increasing concurrency.
- complete #1805 with a quick hack implementation.  that is, maintain
  an internal table of names in the getClosestNSEC() method (either by
  hardcoding the data or allowing the test to build it), and use that
  table to identify the "previous name".  this way we can start other
  tasks depending on #1805 without waiting for the completion of #1803
  and #1804.  When these two tasks are completed we'll complete
  getClosestNSEC() using the getPreviousNode() interface.  That part
  will be deferred to a separate task.
- start #1806 using the quick hack version of #1805 (we can even start
  #1806 once the initial implementation of #1805 is completed, by
  branching from a snapshot version of the #1805 branch while it's
  being reviewed)
- same for #1807 and #1809
- we'll also add a cleanup task to eliminate any duplicates, etc, as a
  result of concurrent development.

I'm going to update the tickets based on this proposal and create new
one(s) that will be necessary as a result of this plan.

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JINMEI, Tatuya