so they actual sequence of events would be 

A: new PouchDB() called
A: afterDBCreated() called, updateSeq initialized to 0
B: db.put() called
A: fetches current updateSeq from the database
A: callback to get(updateSeq), doesn't overwrite updateSeq to whatever was in the db (e.g. 21)
B: writeDoc() called, updateSeq++, updateSeq=1 put in database

because be won't actually get to leveldb until after a is done